2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...

Bolsa Chica Lowlands Restoration Project 

Monitoring Program 

2008 Annual Report 

Prepared for: 

California State Lands Commission 

100 Howe Avenue, Suite 100 South 

Sacramento, CA 95825-8202 

Prepared by: 

Merkel & Associates 

5434 Ruffin Road 

San Diego, CA 92123 

Keith Merkel & Rachel Woodfield 

with: 

Moffatt & Nichol Engineers 

Coastal Frontiers Corporation 

Chambers Group

Bolsa Chica Lowlands Restoration Monitoring 


TABLE OF CONTENTS 

Executive Summary................................................................................................................................ 1 

Introduction........................................................................................................................................... 11 

I. Ecological Monitoring Program ..................................................................................................... 17 

1.1. Vegetation/Habitat Monitoring .................................................................................................................................. 17 

1.2. Soils/Sediment Monitoring......................................................................................................................................... 33 

1.3. Fish Community Monitoring...................................................................................................................................... 37 

1.4. Benthic Monitoring .................................................................................................................................................... 55 

1.5. Water Quality Monitoring .......................................................................................................................................... 66 

1.6. Avian Monitoring....................................................................................................................................................... 72 

General Avian Monitoring ............................................................................................................................................. 72 

Light-footed Clapper Rail Monitoring ........................................................................................................................... 87 

Belding’s Savannah Sparrow Monitoring ...................................................................................................................... 87 

California Least Tern and Western Snowy Plover Monitoring ...................................................................................... 91 

1.7. Non-native Invasive Species ....................................................................................................................................... 96 

II. Physical Monitoring Program ....................................................................................................... 99 

2.1. Inlet Flood Shoal ......................................................................................................................................................... 99 

2.2. Tidal Monitoring ....................................................................................................................................................... 107 

2.3. Beach Monitoring...................................................................................................................................................... 114 

III. Maintenance Dredging Program ................................................................................................ 135 

3.1 Dredging Triggers ...................................................................................................................................................... 136 

3.2 Trigger Analysis......................................................................................................................................................... 137 

3.3 Dredge Triggers - Conclusions and Recommendations ............................................................................................. 140 

3.4 Maintenance Dredging Plan ....................................................................................................................................... 141 

References............................................................................................................................................ 143 

LIST OF FIGURES 

Figure 0-1. Site locator and vicinity map .............................................................................................. 15 

Figure 0-2. Schedule of Bolsa Chica monitoring activities................................................................... 16 

Figure 1-1. Monitoring stations ............................................................................................................. 18 

Figure 1-2. Vegetation and soil monitoring locations ........................................................................... 20 

Figure 1-3. Habitat map (May 2008)..................................................................................................... 22 

Figure 1-4. Full Tidal Basin cordgrass distribution............................................................................... 24 

Figure 1-5. Full Tidal Basin eelgrass distribution ................................................................................. 26 

Figure 1-6. Mean percent cover of native and non-native vegetation by survey area (2008) ............... 29 

Figure 1-7. Fisheries sampling locations............................................................................................... 39 

Figure 1-8. Mean fish density by quarter for large beach seine, otter trawl, and purse seine at Stations 

1 and 2 in the Full Tidal Basin......................................................................................................... 45 

Figure 1-9. Mean fish biomass by quarter for large beach seine, otter trawl, and purse seine at Stations 

1 and 2 in the Full Tidal Basin......................................................................................................... 47 

Figure 1-10. Size class distribution of topsmelt, slough anchovy, kelp bass, and California killifish in 

the Full Tidal Basin in 2008............................................................................................................. 53 

Figure 1-11. Benthic sampling stations ................................................................................................. 56 

Figure 1-12. Mean infauna density and biomass in January and July 2008 by station and tidal elevation 

.......................................................................................................................................................... 61 

Figure 1-13. Full Tidal Basin water quality data - January 2008 .......................................................... 68 

Figure 1-14. Full Tidal Basin water quality data - April 2008 .............................................................. 69 

Figure 1-15. Full Tidal Basin water quality data - July 2008................................................................ 70 

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Figure 1-16. Avian survey zones........................................................................................................... 73 

Figure 1-17. Avian abundance by guild at Bolsa Chica during 2008 surveys ...................................... 80 

Figure 1-18. Avian abundance by habitat type at Bolsa Chica during 2008 surveys............................ 84 

Figure 1-19. Belding’s Savannah sparrow territories (March and April 2008)..................................... 89 

Figure 2-1. Predicted flood shoal area................................................................................................. 100 

Figure 2-2. Full Tidal Basin inlet bathymetry ..................................................................................... 102 

Figure 2-3. Full Tidal Basin accretion and erosion comparisons between surveys............................. 103 

Figure 2-4. Net sediment accretion rate per month ............................................................................. 104 

Figure 2-5a. Minimum daily tidal elevations in the Bolsa Chica Full Tidal Basin (FTB) and at the Los 

Angeles Outer Harbor (LAOH) between January 20, 2007 and December 31, 2008 ................... 109 

Figure 2-5b. Daily differences in lower low tide elevations between the FTB and the LAOH .......... 109 

Figure 2-6. Maximum spring low tide muting..................................................................................... 111 

Figure 2-7. Example comparison of recorded tides (February 2007) at FTB with the ocean tides 

(LAOH).......................................................................................................................................... 112 

Figure 2-8. Location map .................................................................................................................... 115 

Figure 2-9. Beach profile data used in CCSTWS-OC......................................................................... 117 

Figure 2-10. Beach profile survey operations...................................................................................... 119 

Figure 2-11. May 2008 and October 2008 beach widths..................................................................... 124 

Figure 2-12. Long-Term beach width changes, May 1963 to May 2008............................................ 125 

Figure 2-13. Bolsa Chica monitoring period shoreline changes, October 2005 to October 2008....... 126 

Figure 2-14. Long-Term subaerial volume changes, May 1963 to October 2008 .............................. 127 

Figure 2-15. Bolsa Chica monitoring period subaerial volume changes, Oct. 2005 to Oct. 2008 ...... 128 

Figure 2-16. Long-Term shorezone volume changes, May 1963 to October 2008............................. 129 

Figure 2-17. Twelve -Month average berm width at Corps Station 247+88....................................... 131 

Figure 2-18. Twelve -Month average berm width at Corps Station 307+88....................................... 131 

Figure 2-19. Twelve-Month average berm width at Corps Station 424+44........................................ 132 

Figure 2-20. Shoreline changes at upcoast transects, October 2005 to October 2008 ........................ 133 

Figure 2-21. Shoreline changes at downdrift transects, October 2005 to October 2008..................... 133 

Figure 2-22. Subaerial volume changes at upcoast transects, October 2005 to October 2008............ 134 

Figure 2-23. Subaerial volume changes at downcoast transects, October 2005 to October 2008....... 134 

LIST OF TABLES 

Table 1-1. Area of habitats within the Bolsa Chica study area (May 2008). ........................................ 21 

Table 1-2. Vegetation transect monitoring results (2008)..................................................................... 30 

Table 1-3. Soils monitoring results (September 2008)........................................................................... 35 

Table 1-4. Soil grain size analysis results (September 2008)................................................................ 36 

Table 1-5. Summary of fish abundance in the Full Tidal Basin in 2008............................................... 42 

Table 1-6. Summary of fish mass in the Full Tidal Basin in 2008........................................................ 44 

Table 1-7. Water quality measurements taken during quarterly fish sampling in 2008........................ 48 

Table 1-8. Summary of fish abundance in the Muted Tidal Basins in 2008. ........................................ 49 

Table 1-9. Summary of fish mass in the Muted Tidal Basins in 2008. ................................................. 50 

Table 1-10. Summary of fish abundance in the Muted Pocket Marsh in 2008. .................................... 50 

Table 1-11. Summary of fish mass in the Muted Pocket Marsh in 2008. ............................................. 51 

Table 1-12. Minimum and maximum standard length of all fish species captured by quarter at all 

station in 2008.................................................................................................................................. 52 


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Table 1-13. Mean density of infauna in January 2008. ......................................................................... 58 

Table 1-14. Mean biomass of infauna in January 2008......................................................................... 59 

Table 1-15. Mean density of infauna in July 2008. ............................................................................... 59 

Table 1-16. Mean biomass of infauna in July 2008............................................................................... 60 

Table 1-17. Counts of epibenthic invertebrates detected in 1-m 2 quadrats in January and July 2008. . 63 

Table 1-18. Counts of epibenthic invertebrates captured in fishing gear during 2008 quarterly fish 

sampling........................................................................................................................................... 64 

Table 1-19. Summary of 2008 survey dates and number of birds and species observed...................... 76 

Table 1-20. Avian abundance by survey (2008).................................................................................... 77 

Table 1-21. Belding’s Savannah sparrow territories at Bolsa Chica in 2007 and 2008 ........................ 90 

Table 1-22. 2008 California least tern reproductive success for each nesting location. ....................... 93 

Table 1-23. 2008 Western snowy plover reproductive success for each nesting location. ................... 94 

Table 2-1. Net increase in inlet sediment volume in comparison to pre-opening conditions. ............ 101 

Table 2-2. Summary of spring high and low tides............................................................................... 110 

Table 2-3. Beach nourishment history................................................................................................. 116 

Table 2-4. Statistical range and depth of closure at Bolsa Chica area transects.................................. 122 

Table 2-5. Beach width measurement program summary statistics, Jan. 2007 to Dec. 2008. ............ 130 

Table 2-6. Range and depth of closure at Bolsa Chica area transects. ................................................ 130 

LIST OF APPENDICES 

Appendix 1-A. 2008 Field Survey Dates 

Appendix 1-B. Sampling Location Coordinates 

Appendix 1-C. Cordgrass Monitoring Photos 

Appendix 1-D. Avian Guild 

Appendix 1-E. Avian Abundance by Zone in 2008 

Appendix 1-F. Final Report Western Snowy plover Nesting at Bolsa Chica, 2008 

Appendix 2-A. Monthly Tide Plots 2008 

Appendix 2-B. Bolsa Beach Profile Plots 

Appendix 2-C. MSL Beach Width 

Appendix 2-D. Sediment Volume Data 

Appendix 2-E. MSL Beach Width Measurements 

Appendix 2-F. US Army Corps Beach Width Measurements 


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BOLSA CHICA LOWLANDS RESTORATION PROJECT 


Annual Report - 2008 

EXECUTIVE SUMMARY 

The construction phases of the Bolsa Chica Lowlands Restoration Project were principally complete 

by the end of 2006, including the opening of the Full Tidal Basin (FTB) to the ocean in August 2006. 

This report presents the biological and physical monitoring program data collected in 2008, 

documenting the conditions within the restored areas two to three years post-restoration. 

The biological, physical, and beach monitoring programs reported in this annual report were conducted 

following the Bolsa Chica Lowland Restoration Project Biological Monitoring and Follow-up Plan and 

the Bolsa Chica Lowlands Restoration Project Beach Monitoring Plan, both prepared by the U.S. Fish 

and Wildlife Service in 2001. The monitoring team included Merkel & Associates, Moffat & Nichol 

Engineers, Coastal Frontiers, and Chambers Group, Inc. The findings are summarized in the following 

sections. 

VEGETATION/HABITAT 

The distribution, composition, and evolution of vegetation communities and unvegetated habitats were 

monitored through the use of aerial photography and quantitative transect methods. The May 2008 

assessment of habitats at Bolsa Chica mapped ten vegetated and seven non-vegetated habitats within 

the 402-ha (994-acre) study area. 

Open water and salt panne were the most extensive unvegetated habitats. Southern coastal salt marsh 

was the most extensive vegetated habitat, occurring primarily as a fringe to salt panne in the Seasonal 

Ponds and Future Full Tidal Basin, while providing nearly complete cover in the Muted Tidal Basins 

(MTBs). In 2008, only the west MTB was open to tidal influence and the marsh there had had limited 

time to respond prior to the monitoring. It is anticipated that this basin and the central and east MTBs 

will have shifts in marsh distribution in the coming years as all basins are opened to the FTB. The 

lowest lying areas will be converted to open water and mudflat, while marsh will be able to expand 

into higher areas previously dominated by non-native weeds, once they are eliminated by the salt water 

influence. The MTBs were designed to support 51.1 ha (126.3 acres) of salt marsh habitat. In 2008 

the three basins had a total of 49.8 ha (122.9 acres) of salt marsh. 

Salt marsh distribution is also expected to change in the FTB, particularly on Rabbit Island as lowlying 

marsh continues to convert to mudflat. The FTB was designed to eventually support 7.7 ha (19.1 

acres) of pickleweed. In 2008, approximately 4.9 ha (12.4 acres) of coastal salt marsh were present in 

the basin. Salt marsh will be gained at the higher elevations of Rabbit Island as non-native vegetation 

continues to convert to mid and high marsh. Additionally, pickleweed on the cordgrass bench in the 

FTB is expected to expand along the base of the riprap in the coming years. 

Cordgrass (Spartina foliosa) and eelgrass (Zostera marina) were transplanted throughout the FTB in 

August 2007. By August 2008, one year post-transplant, the eelgrass had doubled in distribution to 

cover 0.8 ha (0.9 acre) and is expected to expand substantially in the coming years. Approximately 

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196 m 2 of cordgrass had become established in the FTB one year post-transplant. It is expected that 

the cordgrass will expand to form continuous patches suitable as habitat for light-footed clapper rails 

(Rallus longirostris levipes) within four to five years of transplant. 

Investigations of plant species composition along nineteen transects in the restored areas found the 

Muted Pocket Marsh (MPM) to support the most diverse salt marsh habitat, with minimal non-native 

species. Rabbit Island in the FTB was the second most diverse, but had a higher component of weedy 

species, particularly iceplants. A population of the rare plant coast woolly heads (Nemacaulis 

denudata var. denudata) persists on Rabbit Island and will need immediate protection through removal 

of the iceplant that is encroaching on its remaining populations. The salt marsh in the MTBs is low in 

diversity, but forms a dense canopy of pickleweed (Sarcocornia pacifica) that is heavily used by 

Belding’s Savannah sparrows (Passerculus sandwichensis beldingi) for nesting each year. 

The next full vegetation monitoring event, including aerial photography, habitat mapping, and transect 

surveys, will be conducted in summer 2011 (Year 5) as called for in the Monitoring Plan. Additional 

photography and habitat mapping will be done in 2009 to document interim conditions. 

FISH COMMUNITY 

The 2008 fish community sampling was completed in January, April, July, and October. Sampling 

was performed during daylight hours at two stations in the FTB, one in the MPM, and two in the 

MTBs. Sampling equipment included an otter trawl, purse seine, large beach seine, and small beach 

seine as appropriate for the station depth and accessibility. Captured fish were identified, counted, 

measured, and weighed. Physical water quality parameters were measured coincident with the fish 

sampling efforts. 

A total of 42 fish species were captured in 2008 at all stations. Thirty-nine species were captured in 

the FTB, dominated by topsmelt (Atherinops affinis) (46% of the total catch), California killifish 

(Fundulus parvipinis) (6% of the total catch), and California grunion (Leuresthes tenuis) (9% of the 

total catch). Anchovy (Anchoa sp.) comprised only 7% of the total catch and were present primarily in 

July. The other species captured were increasingly associated with structured habitats due to the 

spread of eelgrass habitat, particularly in the southern half of the basin. Fish densities were generally 

low in January and April and much higher in July and October, driven primarily by the number of 

atherinids captured. 

Ten fish species were captured in the west and central MTB in 2008. Only the west MTB was directly 

open to the FTB. Topsmelt and killifish were the most abundant species. Diversity and biomass are 

anticipated to increase as the MTBs are all opened to the tidal influence of the FTB in the future. 

The MPM, which is hydrologically separate from the restoration project area, was generally found to 

be low in diversity but high in abundance of species foraged on by many birds. Nine species were 

captured, with topsmelt and California killifish the most abundant year round, reaching their peaks in 

July. Staghorn sculpin (Leptocottus armatus) and longjaw mudsucker (Gillichthys mirabilis) were 

occasionally abundant. 

The restoration project and creation of the FTB has increased the availability of important bay habitat, 

provided nursery functions for many species of marine fish, and thereby improved southern California 

fisheries resources. Nearly every fish species captured during the 2007 and 2008 monitoring was 

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represented by juvenile size classes, demonstrating the linkages between the basin and coastal 

fisheries, and the role of the basin as nursery habitat for spawning or post-larval dispersal. 

The Bolsa Chica Steering Committee has decided to conduct an additional year of fisheries monitoring 

in Year 3, which was initiated in October 2008 and will extend through July 2009. The next 

monitoring is then scheduled to occur in Year 5, with sampling events in October 2010, and January, 

April, and July 2011. 

BENTHIC COMMUNITY 

Assessments of benthic infauna and epifauna were conducted in January and July 2008 at three stations 

in the FTB. To sample the benthic infauna, three replicate sediment cores were collected from the 

+0.3-m (+1-foot) NAVD elevation and from the -0.6-m (–2-foot) NAVD elevation and rinsed through 

a 1.0-mm sieve. Organisms from each sample were transported to the laboratory to be identified to the 

lowest practical taxonomic level, counted, and weighed. Epibenthic invertebrates were assessed using 

1-m 2 quadrat at each of the sampling points and tidal elevations. All epifaunal organisms were 

identified and counted. Additionally, during the completion of fish studies described above, the 

incidental by-catch of epibenthic invertebrates was collected, identified, and counted to further 

enhance the detection of epibenthic organisms. 

As expected, considerable variability was observed in the infaunal invertebrate community due to the 

limited replication and frequency of sampling, variations in sediment type within and between stations, 

and the patchiness that is characteristic of benthic invertebrate communities in general. However, the 

two sampling events during the second year post-restoration did serve to document that the creation of 

the FTB has provided benthic food resources available to birds, fish, and other invertebrates. The 

created basin was found to support nine phyla of infauna, with polychaetes the dominant taxa (61% of 

the total), followed by tanaids and bivalves (21% and 4% of the total, respectively). Benthic 

monitoring conducted during the comparable second year post-restoration at Batiquitos Lagoon (1998) 

found the density of infauna there to be very similar, indicating the FTB is performing as expected for 

a created tidal embayment. 

The quadrat sampling to characterize epibenthic communities did not provide a good representation of 

the invertebrates present. Most epibenthic organisms are highly mobile and had vacated the mudflat 

shoreline during the low tides targeted for the survey work. However the tracking of epibenthic 

invertebrates in the fishing gear documented considerably more diversity due the greater area and 

depth range sampled. Species seen in high numbers in 2008 were the pink shrimp Pandalus sp., the 

small kelp humpback shrimp (Hippolyte clarki) commonly associated with eelgrass, various tunicates, 

B. gouldiana, and Argopecten ventricosus. Six non-native species were identified, including the 

Japanese mussel (Musculista senhousia), a highly invasive non-native mussel present in many 

California bays and estuaries and detected during the first biological monitoring event in October 

2007. 

Epibenthic invertebrates present after the opening of the basin to tidal influence were all marine 

species associated with estuarine or bay environments. It is expected that the species list will continue 

to expand over time as additional sampling is conducted. These macroinvertebrates also provide an 

important prey base for fish and birds in the basin. 




The Monitoring Plan calls for benthic monitoring to occur again in Years 5 and 10 post-restoration, 

with sampling events scheduled for January and July of 2011 and 2016. 

WATER QUALITY 

Water quality monitoring was conducted in January, April, and July 2008 using both tended and 

untended continuous recording instrumentation. The deployed units were programmed to log water 

depth, temperature, dissolved oxygen (DO), turbidity, and salinity at 20-minute intervals at two 

stations within the FTB, one in at the north end and other at the south end of the basin. Unfortunately, 

water quality monitoring in 2008 was severely impacted by repeated instrument failures, which limited 

comparisons between stations in several cases. 

The water quality conditions observed in the FTB in 2008 showed the tidal marine influence that exists 

in the basin, reflecting the daily and monthly tidal fluctuations seen in the open ocean. All parameters 

were well within acceptable ranges to support the developing fish, invertebrate, and vegetation 

communities, and are indicative of a well-flushed marine environment. On-going physical monitoring 

of the condition of the inlet and the flood shoal is important to ensure proper circulation of the basin 

and maintenance of good water quality. 

In the April and July months, the slow-circulating waters at the northern end of the basin had higher 

water temperatures because of increased solar heating. The better circulated waters of the southern 

portion of the basin were more influenced by cooler oceanic water, maintaining lower temperatures 

during the warmer months. Very little difference in temperature was seen between the two stations 

during the January sampling. The FTB closely matched sea surface temperatures in the ocean in the 

winter, and had higher temperatures than the ocean in the summer months, a condition typically seen in 

other coastal embayments in the region. 

Dissolved oxygen levels were within the expected range and reflected the strong influence of diurnal 

tidal flow, with DO levels rising and falling with tides as water masses with differing physical and 

biotic conditions were exchanged. The condition of the FTB inlet remained suitable to provide enough 

tidal circulation throughout the basin to maintain DO levels generally well above 5.5 mg/L, with daily 

tidal peaks in the 7.5 to 8.5 mg/L range, even during the warm July month when unhealthy drops in 

DO can be observed in poorly circulated systems. 

Large gaps in the salinity datasets limited the amount of interpretation that could be done, however the 

data available reflected the absence of significant freshwater input into the FTB, with salinities similar 

to typical oceanic salinities for most of the year. Turbidity generally ranged between 0 and 15 NTU at 

both stations, though interference with the sensor by passing octopus, opisthobranchs, and algae, as 

well as laid egg masses, affected the acceptability of some of the data. 

The next monitoring is scheduled to occur in Year 5, with sampling events in October 2010, and 

January, April, and July 2011. 

AVIAN COMMUNITY 

Saturation surveys of the avian surveys were conducted in February, April, June, August, October, and 

December in 2008. Diversity ranged from 82 to 114 species per survey and was highest during 

December and February. A total of 135 species was observed in 2008, for a grand total of 145 species 

observed since the start of the monitoring period (October 2007 to December 2008). The number of 




individual birds observed was fairly consistent over the year with the exception of June, when the 

count was reduced by more than one half due to the absence of large groups of shorebirds. 

Throughout most of the year western sandpiper (Calidris mauri) was the most common species, with 

shorebirds the most abundant guild overall. This changed in June when most of the shorebirds left 

Bolsa Chica for their breeding grounds and were replaced by species that nest in the area. These 

species were mostly the aerial fish foragers (primarily terns), but also included some of the larger 

shorebirds such as black-necked stilt (Himantopus himantopus), and American avocet (Recurvirostra 

americana). The second most abundant guild was dabbling ducks/geese, which had high counts in 

February, April, and December but remained present year round in smaller numbers. 

Mudflats and inundated salt panne were the most utilized habitat type, although species richness was 

highest in the salt marsh. In 2008 the FTB was utilized by 49.7% of all birds observed, representing 

103 species. Nest Site 1 (NS1) in the FTB was highly utilized by aerial fish foragers, particularly 

during the April through August surveys when the terns and skimmers were nesting. The Future Full 

Tidal Basin (FFTB), Seasonal Ponds, and MTBs were very important habitat for dabbling ducks, 

shorebirds, and upland birds. The most abundant upland bird was Belding’s Savannah sparrow, which 

utilized the pickleweed-dominated salt marsh. The Muted Pocket Marsh is highly utilized by 

shorebirds and dabbling ducks and had even more birds per hectare than the FTB. 

Surveys for the state endangered Belding's Savannah sparrow were performed in April and May 2008. 

Two complete surveys were done in 2008 in order to improve the reliability of the number of 

territories recorded. A total of 177 territories were identified within the study site in April 2008 and 

208 territories in May 2008. These numbers are lower than those recorded in 2007, but comparable to 

the counts in 2006. Territories appeared to be relatively evenly dispersed throughout areas where 

pickleweed-dominated salt marsh occurred. Using the area of salt marsh available and the maximum 

number of territories recorded, the average territory size was estimated to be 1,836 m 2 , much larger 

than the average territory size noted in the available literature (304 m 2 to 626 m 2 ). While the available 

habitat would suggest low-density occupancy by Belding’s Savannah sparrow, the highly fragmented 

nature of the present salt marsh results in considerable area that is unsuitable for breeding use. As the 

system matures, it is expected that more of this area will become suitable and will be occupied by the 

sparrows. The FFTB supported the most territories, followed by the MTBs, then Seasonal Ponds. 

California least tern (Sternula antillarum browni) nest monitoring occurred on North Tern Island 

(NTI), South Tern Island (STI), NS1, Nest Site 2 (NS2), and Nest Site 3 (NS3). The terns nested 

primarily on STI and NS1, although one unsuccessful nest was located in the Seasonal Ponds in Zone 

11. The least terns did not utilize NTI, NS2, or NS3. From an estimated number of 217 pairs, a total 

of 432 eggs were laid in 242 nests. These numbers are a slight increase from those of 2007. The 

average clutch size was 1.8 eggs per nest and the first least tern fledgling was recorded on 23 June. 

California least tern nest predation was low at 19 (7.9% of all nests) nests. Seven (2.9%) nests were 

abandoned prior to hatching, and one nest was lost to flooding. Fledgling success for the 2008 season 

ranged from 100-150 fledglings, for a rate of 0.41 to 0.62 fledglings per nest. This is compared to 15 

fledglings in 2007 and a rate of 0.07 fledglings per nest. 

The western snowy plover (Charadrius alexandrinus nivosus) nested on STI, NS1, NS3, and a number 

of cells within the Seasonal Ponds, with a total of 67 nests. From the 193 total eggs laid, 174 chicks 

were produced. Two of the 67 nest attempts were lost to predators; however, three nests were 




abandoned. Of these, 174 total chicks were produced in 2008 and a minimum of 57 and a maximum of 

109 (32.8 to 62.6%) chicks survived to fledge. The minimum fledgling estimate per nest (0.85 

fledglings/nest) is slightly below the average (0.95 fledglings/nest) of the study years. The maximum 

estimate of fledglings per nest (1.62 fledglings/nest) would exceed the previous high of 1.47 in 2005. 

Avian monitoring recommendations include continuing the Belding’s Savannah sparrow monitoring 

program to include a minimum of 2 surveys per breeding season and implementation of the 

management recommendations detailed in the snowy plover report (Appendix 1-F). 

INLET FLOOD SHOAL 

The rate and distribution of sand accretion in the FTB inlet was assessed by bathymetric survey in 

January and June 2007, and in January, July, and December 2008. The volume and distribution of 

accumulated sand was compared to the pre-basin opening conditions of August 2006. A small shoal 

had formed in the inlet by January 2007 and continued to expand through 2007 and 2008. The net 

volume of sediment (composed entirely of littoral sand) accreted within the assessment polygon was 

compared to the pre-opening conditions and had reached 204,923 m 3 by December 2008. This can be 

expressed as a total rate of volume change from the basin opening through December 2008, roughly 28 

months later, of approximately 240 m 3 /day. It is important to note, however, that this average rate 

does not represent the actual accretion per day, as deposition and erosion occurred throughout the 

period at an uneven rate. 

To examine this variable rate, the contour plots of each survey were compared to each other to quantify 

areas of erosion and accretion between surveys. As anticipated, there was a large input of sand 

between the basin opening on August 24, 2006 and the first survey on January 19, 2007, with an 

average of 402 m 3 /day. The influx rate then decreased between subsequent surveys, to an average of 

230 m 3 /day in 2007 and 134 m 3 /day in 2008. 

The flood shoal volume, area of shoaling, and shoaling rate have occurred similarly to processes 

predicted during the project design. The variable seasonal influx of sand, and added complication of 

provision of local source sand in the pre-filled ebb bar and beach around the mouth, is expected to 

have played a role in the high early infill rates. Further, early infill would have also added sand to the 

oversized entrance channel, thus decreasing the observed rate of shoaling from the true rate since the 

flood shoal survey assessment area does not extend out fully into the entrance channel. Subsequent 

reduced rates of infill may indicate more rapid achievement of relative stability following the initial 

system loading. 

Future monitoring of the flood shoal will occur in January and June of 2009 and 2010. 

TIDAL MONITORING 

Accretion of sand within the flood shoal of the FTB is the most important factor causing tidal lag and 

muting. Tidal monitoring provides a means of tracking the lag and muting and providing information 

necessary to determine the need for maintenance dredging to ensure proper physical and ecological 

system functioning. 

Tidal monitoring began in the FTB in December 2006 and was continuous throughout 2008. 

Comparison of the lower low tide data for each day showed that the FTB did not completely drain to 

local oceanic sea levels (as measured at Los Angeles Outer Harbor [LAOH]) during lower low spring 




tides and that tidal muting was becoming more pronounced through the 2008 monitoring period as the 

flood shoal built in the inlet. In 2008, lower low tides in the FTB only went as low as LAOH during 

very mild neap tides. 

From January to December 2007, tidal muting within the FTB had increased by an average of 0.07 m. 

The winter of 2007-2008 marked a considerable change. From December 2007 through April 2008, 

tidal range decreased by approximately 0.24 m and tidal muting increased by an equivalent amount. 

From May 2008 through the remainder of the year, muting and tidal range remained fairly consistent 

with little additional muting being evidenced. By the end of 2008, the tidal range within the FTB had 

been reduced from that of the open coast by an average of approximately 0.6 m with the maximum 

observed range loss reaching 0.86 m during July 2008. The collected data indicated the presence of 

seasonal variation in muting, with an increase in the winter and mid-summer months when larger than 

average tidal ranges occur, and decreased muting during the spring and fall months when smaller than 

average tidal cycles occur. There were also fairly substantial changes in muting rates between months, 

including a relatively precipitous acceleration in the extent of muting in the system overall beginning 

in January 2008 through approximately April 2008, after which time the spring tide low tide muting 

remained fairly constant through the remainder of the year. 

The lag of the low tide in the FTB compared to that in the ocean was approximately 78 minutes on 

January 19, 2007, 114 minutes on January 21, 2008, and 288 minutes by December 13, 2008. 

It was expected that the tidal range would gradually decrease and muting of the low tide would 

increase over time. It was further expected that muting and phase lag would become more severe due 

to effects of flood shoal development in the FTB until the implementation of the first dredging event, 

occurring in 2009. Preliminary engineering predictions of the effect of shoaling on tidal muting were 

that the tide range would reach 2.256 m and muting of the low tide to reach 0.244 m. Generally, the 

muted tidal range under the post-construction condition met the target of the “full tidal range” 

objective of the project planning documents during 2007, but with further shoal development in 2008 

the range substantively diminished. 

During preliminary engineering, tidal predictions were based on a theoretical average spring tidal 

condition, not the maximum spring tide condition. Because of the high importance of the low tide 

muting and lag to the drain-fill hydraulics of the MTBs, these maximum drain-out conditions are of 

key interest as they pertain to proper functioning of the MTBs. Although the FTB would still be 

considered fully tidal in 2008, the diminishing drainage from the basin reached such a point as to 

restrict drainage from the open west MTB. 

Although the Freeman Creek water control structure slide gates remained closed during 2008, the 

muting of the FTB would have otherwise restricted the full drain-out potential if they had been open, 

since the drainage of Freeman Creek is by gravity to the FTB. FTB water levels were higher than the 

creek in 2008 and would have precluded proper drainage. 

As a result of the shoal-associated muting and its controlling influence on the functioning of the MTBs 

and Freeman Creek, along with other variables (shoal volume and area of low intertidal habitat lost), 

maintenance dredging was warranted in 2008 and first scheduled to occur in the fall of 2008. 

Continuous tidal monitoring will continue in 2009. 




BEACH MONITORING 

Beach profile data were obtained in May and October 2008 and compared to historic data and data 

collected in 2007. Historically, the beaches along the Bolsa Chica study area have benefited as the 

downdrift recipient of the Surfside-Sunset nourishment material. During the 34-year period between 

1963 and 1997, the beaches advanced at four of the five historical transects included in the Bolsa Chica 

beach monitoring program. Mean sea level (MSL) shoreline advance ranged from 14 m to 71 m within 

the present study area. The only occurrence of shoreline retreat during the 34-yr period was a loss of 

18 m at a transect located at Huntington Cliffs. The volume of sand above MSL increased in parallel 

to the beach width changes during the period. The shorezone volumes in the study area, which 

incorporate the sediment changes further offshore, increased at all of the sites. The greatest gains 

typically occurred prior to 1978. 

During the three-year period encompassing the last year of the construction of the Bolsa Chica 

Lowlands Restoration Project and the first two years post-restoration (October 2005 to October 2008), 

the shoreline advanced at the three transects located north of the entrance channel, with the greatest 

gain being 24 m. Shoreline retreat predominated at the survey sites located south of the entrance 

channel, with beach width changes ranging from a gain of 1 m to a loss of 14 m. The subaerial volume 

changes were very similar to the beach width changes, with gains occurring north of the entrance 

channel and losses predominating south of the entrance channel. While it is not possible to 

quantitatively assess shorezone volume changes during the recent three-year period (the October 2005 

profile does not extend below the waterline), a trend of shorezone volume loss has prevailed at each 

transect between January 2007 and October 2008. This may be attributable dispersal of the pre-filled 

ebb bar and natural erosion between Surfside-Sunset nourishment intervals. 

Approximately 158,000 m 3 of sediment was deposited in the lagoon during the 17-month period 

between August 2006 and January 2008. Sedimentation was reduced substantially during the second 

year (11-month period between January 2008 to December 2008) to approximately 46,000 m 3 . While 

a small fraction of this material may have resulted from redistribution of basin sediments or aeolian 

processes, nearly all of the sediment has entered the basin from the ocean. It is possible that the high 

shoaling rate during the first year was a transient effect attributable to inlet stabilization, and increased 

propensity for sedimentation due to the proximately of the pre-filled ebb bar and widened beaches 

adjacent to the inlet. The reduced shoaling rate during the second year is likely attributable to a 

reduced tidal prism due to high initial shoaling rates and the stabilization of the aforementioned local 

sediment sources (nourished beaches and ebb bar). Nevertheless, the shoaling rate measured during 

the initial 17-month period is on the same order of magnitude as the alongshore sediment transport 

rates previously developed for Orange County (estimated to range from 108,000 m 3 /y to 125,000 

m 3 /y). As a result, particular attention is warranted in monitoring the flood shoal accumulation rates 

following the recent 2008 dredging activities to understand if the initial sedimentation was transitory or 

should be expected following future dredging episodes. 

In the event that the high sediment trapping rates detected following the initial inlet opening persist 

following the upcoming dredging activities forecast for 2009 (i.e., the sedimentation rates are not 

transitory), these rates are of a significant magnitude to be of major concern to alongshore transport in 

the littoral cell. If left unchecked and unmanaged, the primary implication of a substantial reduction of 

the alongshore sediment supply is shoreline erosion downdrift of the entrance channel. The Bolsa 

Chica project, however, incorporates two sand management measures to actively address the potential 

for downdrift erosion by eliminating or substantially reducing the net long-term loss of sand 




downcoast. To compensate for anticipated short-term sediment losses from the littoral budget due to 

the natural formation of an ebb bar, initial lagoon shoaling, and fillet formation along the jetties, the 

ebb bar located offshore of the entrance channel was pre-filled, and supplemental sand was placed as 

beach nourishment adjacent to the channel at the time of construction. These pre-fills were intended to 

minimize littoral sand loss to ebb bar formation and provide supplemental sand for early inlet 

stabilization. In addition, the long-term project sediment management plan provides for periodic 

down-coast beach nourishment using sediment derived from the FTB during maintenance dredging 

operations, restoring the sediment lost from the littoral budget to the downdrift beaches. 

MAINTENANCE DREDGING AND DREDGING TRIGGERS 

Parameters of tidal muting, beach width, loss of subtidal habitat, closure risk, muted tidal basin 

function, and water quality were analyzed to evaluate the functioning of the system and determine 

when dredging should be performed. Some of these parameters have pre-established triggers including 

tidal muting, beach width, and loss of subtidal habitat. Other parameters do not presently have 

established criteria for triggering a dredging event. 

In reviewing the established dredging triggers, it is clear that some of the triggers may never be met 

except under extreme circumstances, while more significant triggers may exist that have not as yet 

been quantified. Chronic beach erosion triggers are not likely to be met because of the ongoing 

replenishment at Surfside-Sunset and the program’s effect on long-term beach growth trends. 

Similarly, acute erosion triggers are not likely to be met due to the generally broad beach profiles at 

trigger point transects. It is more likely that maintenance dredging will be required to address an 

intrinsic system need related to the functionality of the MTB tidal control structures and Freeman 

Creek. Final triggers to address this issue will need to be set once all of the MTBs are open to the FTB 

and have operated under both normal and muted FTB conditions. 

During periods in 2008 when the average of the lowest spring tides in each tide series achieved 

elevations at or below –0.05 m NAVD, the west MTB functioned well. When the average of the 

lowest spring tides in each tide series achieved elevations at or above 0.28 m NAVD, the function of 

the west MTB was impaired and operational ranges were necessarily curtailed to avoid flooding above 

designed operational levels. As an interim-operating trigger for maintenance dredging, it is 

recommended that the occurrence of four or more consecutive low spring tides in the FTB that fail to 

achieve low elevations of 0.12 m NAVD or lower, on a running average basis, should suggest dredging 

is likely necessary. It is anticipated that maintenance triggers will need to be further modified in the 

future as the central and east MTBs are opened to tidal flows. 

Recommendations 

• Modify the expectations of tidal range in the FTB from 2.75 m to 2.29 m, with tidal elevations 

ranging from 2.02 to -0.27 m NAVD. 

• Remove the dredge trigger of the Mean Low Tide muting of 0.152 m. 

• Add an interim trigger of the rolling average of four consecutive lowest tides achieved during 

spring tide series exceeding 0.12 m NAVD, described in detail in Section 3. 

• Continue the tidal monitoring program with frequent reporting to show effects of the first 

maintenance dredging event occurring in 2009 and to assess the relationship between flood 

shoaling and tidal muting. 




• Continue the tidal monitoring program to show effects of the first maintenance dredging event and 

to assess the relationship between flood shoaling and tidal muting. 

• Dredge accumulated sands from within the flood shoal in winter 2008/2009 as scheduled since 

effects of the flood shoal impede the tidal ebbing from the entire site and adversely effect function 

of the MTBs and Freeman Creek Water Control structure. 

• The beach width dredging trigger should be modified to reflect a more current set of beach width 

data that includes the effects of the 2002 Surfside-Sunset nourishment and the scheduled 2009 

Surfside-Sunset nourishment. In addition, the trigger should indicate that dredging should be 

performed when the beach width is less than two standard deviations from the mean beach width, 

since being greater than two standard deviations does not indicate a need for dredging. 

• Consider phasing out the beach width triggers, as these are not likely to ever be tripped prior to 

maintenance dredging triggers that address muting and impairment of the MTBs. 

• Continue bathymetric monitoring, and anticipate another maintenance dredging event in two years. 

Additional adjustments to dredging triggers are anticipated in response to future performance analysis 

of the MTBs and additional analysis of shoaling after the first maintenance dredging cycle is 

completed. 

The first maintenance-dredging event is scheduled to occur in early 2009. For future dredging events, 

consideration should be given to dredging to the permitted depth of the final engineering design depths 

to extend the period between maintenance events. Dredging at the time of initial construction was not 

completed to full design depths within the maintenance basin. If deepening of the maintenance basin 

were completed, this would garner additional time between dredging events and would improve 

dredging efficiency by capturing a greater volume of sediment in a more localized and recoverable area 

nearer the inlet. 

Additionally, the pre-dredging contracting process can consume a considerable period of time and thus 

work should be completed to streamline and pre-prepare to the maximum extent practical prior to 

maintenance triggers being tripped. This would allow for a reduced period over which the system 

functions in an impaired condition prior to completing maintenance dredging. To accomplish this 

would require: preparation of the majority of the plans and specifications, completion of permitting 

based on a maintenance basin plan and dredge volume range, preparation of bid and contract 

documents, and obtaining maximum flexibility for the dredging window of work. Long-term Corps 

permits for maintenance dredging are possible, including ten-year permits to include dredging triggers 

and pre-dredging notification and approvals that are considerably shorter than applying for a new 

permit each time dredging is to be performed. 




INTRODUCTION 

BACKGROUND 

The Bolsa Chica Lowlands are located in Orange County, California, between Bolsa Chica Mesa on 

the northwest and Huntington Beach on the southeast (Figure 0-1). In 1996, eight state and federal 

agencies entered into an agreement to conduct wetland acquisition and restoration at the Lowlands. 

Following project planning, land purchase, restoration design, permit acquisition, and publication of a 

Final Environmental Impact Statement/Final Environmental Impact Report, restoration construction 

began on October 6, 2004. The project involved the creation of a Full Tidal Basin (FTB) and 

restoration of Muted Tidal Basins (MTB) by constructing an ocean inlet north of Huntington Mesa. 

To create the FTB, approximately 1.57 million m 3 of material were excavated from within the Bolsa 

Chica Lowlands to create a basin of a general depth of –1m NAVD, bounded by intertidal flats. The 

excavated sand was distributed on the adjacent beaches from March to June 2006 (102,500 m 3 , divided 

evenly to the north and south of the future inlet) as well as placed offshore from November 2005 to 

May 2006 to form an ebb bar (929,326 m 3 ) outside of the future inlet. Approximately 531,354 m 3 of 

material was placed to form the berms that bound the basin and three nesting areas. Remaining 

material was hauled off-site. Jetties were constructed to form the ocean inlet to the basin from March 

through June of 2006. 

The FTB was opened to the ocean on August 24, 2006. The basin was designed to support 71.0 

hectares (ha) (175.5 acres) of non-wetland waters, 49.6 ha (122.6 acres) of tidal flats, and 7.7 ha (19.1 

acres) of pickleweed. In order to keep the inlet open, maintenance dredging is anticipated to be needed 

every two to three years, with dredged sand to be placed on down-coast beaches. 

Water control structures and culverts through the berm were installed to allow regular but muted tidal 

influence from the FTB to each of three MTBs (Figure 0-1), to support 51.1 ha (126.3 acres) of salt 

marsh habitat, and create 17.1 ha (42.3 acres) of tidal flats, 12.3 ha (30.5 acres) of cordgrass habitat, 

and 0.7 ha (1.4 acres) of non-wetland waters. The west MTB was opened to tidal influence from the 

FTB through its water control structure in March 2008, while the central and east basins remained 

closed while additional oil spill and flood control protections were put into place. The restoration 

project involved no changes to the Future Full Tidal Basin, which is currently an active oil production 

field, or the Seasonal Ponds (Figure 0-1). 

2008 SITE CONDITIONS 

The water control structure at the west MTB was opened to tidal influence from the FTB on March 5, 

08. The central and east remained closed, however several heavy rain events, slow seepage through 

the control structures, and designed gravitational flow from the west to central MTB filled the low 

lying areas of all three of the basins, creating open water in areas that were previously dry salt panne. 

The storm events early in the year also raised the water level in Freeman Creek and the Seasonal 

Ponds, creating large expanses of open water during many of the bird surveys. Because the water 

control structures designed to drain Freeman Creek and Seasonal Ponds to the FTB were closed in 

2008 while additional oil spill protections were put in place, water was pumped out of the creek and 

some ponds in May 08 to lower the water level in the ponds to make more foraging habitat available 

for western snowy plovers. 




By the end of 2008, the flood shoal in the FTB inlet had reached its greatest extent as anticipated, and 

the reduction of tidal range in the basin had progressed as well. During low oceanic tides, the blockage 

of the inlet by the shoal prevented the FTB from draining out as fully as it had immediately following 

construction. This resulted in a muting of low tides in the basin, which had an effect on the biological 

communities by increasing the daily durations of tidal inundation in the FTB and on the physical 

functioning of the system, which relies on low tides in the FTB to adequately gravity drain Freeman 

Creek and the Seasonal Ponds. These conditions were anticipated as part of the project design and 

were the triggers that indicated that maintenance dredging at the end of 2008 was warranted. 

Development of the flood shoal and the resulting effects on the biological communities, tidal ranges, 

and maintenance plans are discussed in the following chapters. 

MONITORING PROGRAM 

The follow-up monitoring of the restoration generally conforms to the Bolsa Chica Lowland 

Restoration Project Biological Monitoring and Follow-up Plan prepared by the U.S. Fish and Wildlife 

Service in 2001 (Monitoring Plan)(USFWS 2001a). The Monitoring Plan notes that the purpose of the 

monitoring program is to document the habitat improvements for fish and wildlife, the success of 

revegetation efforts, and the use of the site by endangered species. Additional monitoring elements in 

the Monitoring Plan are intended to ensure that the inlet is properly maintained, constructed nesting 

areas have adequate maintenance, any impacts to sensitive plant species are offset, and that 

construction impacts to Belding’s Savannah sparrow (Passerculus sandwichensis beldingi) were 

minimized. 

The Plan identifies the ecological monitoring objectives as follows: 

• Facilitate evaluation of the effectiveness of the restoration to provide habitat for fish and 

wildlife. 

• Document changes in the ecology of the wetlands environment over time. 

• Provide timely identification of any problems with the physical, or biological development of 

the restored area. 

• Assist in providing a technical basis for resource management of the restored wetland by 

documenting maintenance needs and enhancement opportunities. 

The plan calls for biological monitoring to be conducted during the 2nd, 5th, and 10th years after 

completion of construction. Listed species will be monitored each year. Physical monitoring will be 

conducted in years 1, 2, 3, 5, and 10. 

Immediately west of the Lowlands is Inner Bolsa Bay, which was established as an Ecological Reserve 

in 1973 to be managed by the California Department of Fish and Game (CDFG) (Figure 0-1). On 

August 24, 2006, the Bolsa Chica Lowlands Restoration Project acreage and the Muted Pocket Marsh 

were incorporated into the Ecological Reserve by agreement of the State Lands Commission and 

CDFG. This monitoring program study boundary includes only the restored Lowlands and Muted 

Pocket Marsh, not Bolsa Bay, with the exception that California least tern and western snowy plover 

monitoring was conducted throughout the Ecological Reserve (Restoration Area and Inner Bolsa Bay). 

The Beach Monitoring for this program conforms to the Bolsa Chica Lowlands Restoration Project 

Beach Monitoring Plan (USFWS, 2001b). The Beach Monitoring Plan defines monitoring activities 

and analyses that are expected to assure restoration project-related adverse impacts to area beaches are 

mitigated. 




The State Lands Commission contracted Merkel & Associates, Inc. (M&A) and its team to implement 

the first three years of the Biological and Beach Monitoring Plans. The monitoring team included 

Merkel & Associates, Moffatt & Nichol Engineers, Coastal Frontiers, and Chambers Group, Inc. The 

FTB was opened to the ocean on August 24, 2006, with additional remedial construction activities 

continuing to address various shoreline stabilization issues. Contracting was not in place to initiate 

immediate monitoring until late 2006. However the Year 2 biological monitoring was initiated on 

schedule in Fall 2007. The annual monitoring reports will be prepared by calendar year but will 

include data collected by monitoring year, which is based on a schedule starting in October 2006. 

Therefore the first monitoring report included all data collected from November 2006 through 

December 2007, capturing all monitoring conducted under Year 1 of the monitoring program (October 

2006 to September 2007), as well as the first quarter of Year 2 (October to December 2007) (M&A 

2008a). This second monitoring report includes all data collected from January to December 2008, 

capturing the last three quarters of Year 2 (through September 2008) and the first quarter of Year 3 

(October to December 2008). A schedule of monitoring activities and reporting is presented for 

clarification (Figure 0-2). 

This document serves as the annual report for 2008. It is divided into three primary sections: 

Ecological Monitoring, Physical Monitoring, and Dredging Analysis. Copies of prior reports are 

posted on-line at www.bolsachicarestoration.org. 

In additional to the schedule in Figure 0-2, a table summarizing the dates of each field event during 

2008 is provided in Appendix 1-A. 

HORIZONTAL AND VERTICAL REFERENCE DATA 

The vertical datum used throughout this document is North American Vertical Datum of 1988 

(NAVD88), with units expressed in meters. For purposes of equating this datum to recognized 

biological zonation patterns in tidal marine systems, NAVD88 roughly equates to Mean Lower Low 

Water (MLLW). More precisely, at the project site, NAVD88 lies approximately 0.06 m (0.2 feet) 

above National Ocean Service (NOS) MLLW and 0.79 m (2.6 feet) below NOS Mean Sea Level 

(MSL; NOS, 2007). 

Horizontally geo-referenced data are in meters relative to California State Plane Zone 6, North 

American Datum of 1983 (NAD 83). Area measurements are presented in hectares, with conversions 

to acres provided due to the greater ease with which many readers can envision areas in this unit of 

measurement. Additionally, discussion of sediment accumulation and dredging volumes are presented 

in cubic meters, with conversions to cubic yards due to the prevalence of this unit in the commercial 

dredging field. 

DEFINITIONS AND GEOGRAPHIC REFERENCES 

To assist the reader, this section has been provided to serve as a reference for terminology and 

abbreviations used in this report. In addition, this section includes a map of the Bolsa Chica Lowlands 

and surroundings labeled with place names to assist in following discussions that are geographically 

referenced to particular areas within the site (Figure 0-1). 




Term Abbreviation Notes 

Full Tidal Basin FTB Area: 158.3 hectare (ha)(391.2 acres [ac]) 

Future Full Tidal Basin FFTB Area: 103.8 ha (256.5 ac) 

Muted Tidal Basin MTB Area: 76.6 ha (189.3 ac) (not joined to FTB) 

Seasonal Ponds 

Area: 49.6 ha (122.5 ac) 

Muted Pocket Marsh MPM Area: 14.0 ha (34.7 ac) 

Nest Site 1 NS 1 



South Tern Island STI Inner Bolsa Bay (LETE and SNPL monitoring only) 

North Tern Island NTI Inner Bolsa Bay (LETE and SNPL monitoring only) 

Rabbit Island 

Intertidal island in northwest portion of FTB 

Water Control Structure WCS Gates to regulate tidal flow from FTB to MTBs 


Santa Barbara 

Los Angeles 

Outer 

Bolsa 

Bay 

Muted 

Pocket Marsh 

West 

WCS 

East Garden Grove Wintersburg Channel 

Muted Tidal Basins 

Huntington Beach 

MAP 

AREA 

HUNTINGTON BEACH 

San Diego 

Rabbit 

Island 

Inner 

Bolsa Bay 

North 

Tern 

Island 

Nest Site 1 

Central 

WCS 

Full Tidal Basin 

East 

WCS 

Nest 

Site 2 

Freeman 

WCS 

Freeman Creek 

Future Full Tidal 

PACIFIC OCEAN 

South 

Tern 

Island 

Nest 

Site 3 

Flood Shoal 

Maintenance 

Area 


West Muted Tidal Basin 

Central Muted Tidal Basin 

East Muted Tidal Basin 

Monitoring Program Study Boundary 

0 100 200 400 600 800 

Meters 

Ocean 

Inlet 

Site locator and vicinity map 


Figure 0-1 

Merkel & Associates, Inc.

Bolsa Chica Lowlands Restoration Monitoring 2008 Annual Report 

Figure 0-2. Schedule of Bolsa Chica monitoring activities (Breaks in task numbering reflect analytical or administrative tasks that have not been 

shown) 

2006 2007 2008 2009 

TASK A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D 

Monitoring Year 1 Monitoring Year 2 Monitoring Year 3 

COMPLETION OF CONSTRUCTION 

1.0. Ecological Monitoring Program 

1.1. Water Quality 

1.2. Soils 

1.3. Vegetation/Habitat Mapping 

Aerial Photogrammetry and Georeferencing 

Vegetation Mapping and Groundtruthing 

Vegetation Transect Monitoring 

Eelgrass Monitoring 

Cordgrass Monitoring 

1.4. Fisheries 

1.5. Benthos 

1.6. Avian 

General Avian Surveys 

Species of Special Concern 

California Least Tern Monitoring 

Western Snowy Plover Monitoring 

Belding's Savannah Sparrow Monitoring 

2.0. Physical Monitoring Program 

2.1. Inlet Bathymetric Monitoring 

2.2. Tidal Monitoring 

2.3. Beach Monitoring 

Semiannual Beach Profile Surveys 

Monthly Beach Width Measurements 

5.0. Maintenance Dredging 

Planning and Permitting 

Maintenance Dredging 

7.0. Reporting Program 

7.2. Annual Report 

Activity 

Report 




I. ECOLOGICAL MONITORING PROGRAM 

The ecological monitoring stations were established using direction provided in the Bolsa Chica 

Lowland Restoration Project Biological Monitoring and Follow-up Plan (Monitoring Plan), as well as 

observations made in the field at the time of station determination. Figure 1-1 presents the general 

sampling locations for water quality, benthic infauna, fish, and birds. Appendix 1-A summarizes the 

dates of each field event. Within each of the following sections, more detailed maps of sampling 

locations are presented as needed. 

1.1. VEGETATION/HABITAT MONITORING 

Introduction 

The distribution, composition, and evolution of vegetation communities and unvegetated habitats were 

monitored through the use of aerial photography and quantitative transect methods. The Monitoring 

Plan called for vegetation monitoring to be initiated in Year 2 of the program. 

Methodology 

Habitat Mapping 

To map vegetated and non-vegetated habitats, the Bolsa Chica study area was contract flown on May 

13, 2008 to photograph the site at a scale of 1:4,800 from true vertical position on 9”x9” false-color 

infrared (IR) film. The photos were flown at approximately 1230 hours at a measured FTB tide of 

approximated +0.3m NAVD88. This allowed photography of as much exposed intertidal habitat as 

possible while lighting and weather conditions were suitable for the photography. Additionally, a 

single 1:19,344 true color spot aerial photograph was taken coincident with the IR imagery. This 

photograph assisted in providing an additional tool for habitat interpretation and mapping as well as 

served as a base map for all field monitoring efforts and reporting. 

Following survey flights, the aerial images were digitally scanned and georeferenced to create a tile 

mosaic image for interpretive mapping. Once the images were correctly registered to the project site, 

heads-up digitization of vegetation boundaries was performed to map communities in accordance with 

CDFG Holland classification codes (Holland 1986). Additional codes were used as necessary to 

supplement the vegetation codes with biologically important marsh zones, non-vegetated communities, 

and marine habitats that are lacking in the Holland system. These codes followed the Nearshore 

Habitat Classification system developed for coastal marine mapping (M&A 2003). 

The draft digitized habitat maps were printed and taken into the field for ground-truthing. Once 

completed, the habitat maps were updated and map products and summary statistics of habitat acreage 

and distribution across the various project components were generated. Future mapping efforts will 

examine habitat change relative to spatial and numeric parameters reported here. 

Eelgrass (Zostera marina) was introduced into the FTB through a transplant conducted by M&A in 

August 2007. Eelgrass was harvested from the Cabrillo Beach region of the Port of Los Angeles and 

transplanted to 15 sites in the FTB in 45x5m blocks. A total of 0.4 hectare (0.9 acre) of eelgrass was 

transplanted. The distribution of eelgrass present one year later was mapped on June 30, 2008 by a 

separate methodology from the other vegetation mapping described above. The FTB was surveyed for 

eelgrass from a boat using a sidescan sonar operating at 600 kHz scanning out 20 


Muted 

Pocket Marsh 

STATION 1 

wq1 

STATION 3 

(benthic only) 

East Water 

Control Structure 

Tidal 

Monitoring 

Station 

wq2 

STATION 2 

Water Quality Stations 

Inlet Bathymetric Monitoring 

Avian and Vegetation Study Boundary 

0 100 200 400 600 800 

Meters 

Monitoring stations 


Figure 1-1 




meters on both the starboard and port channels to cover a 40-m wide swath. Following completion of 

the survey, sidescan sonar traces were geographically registered, plotted on the geo-rectified aerial 

image described above, and the eelgrass digitized to calculate the amount of coverage and show its 

distribution. 

Cordgrass (Spartina foliosa) harvested from upper Newport Bay was transplanted by M&A and 

agency and community volunteers into the FTB on August 21 and 22, 2007. It was planted as both 

plugs with native sediment and as bundles of individual bare-root stems in 45x5m blocks at 14 sites 

along the northeastern and western shore of the FTB, including Rabbit Island. A total of 0.3 ha (0.7 

acre) of cordgrass was transplanted. The distribution of cordgrass in the FTB was mapped one year 

later on August 20 and 21, 2008 by walking the perimeter of the cordgrass patches at each transplant 

site with a hand-held differential GPS (dGPS) unit. Groups of plants that were less than one meter 

apart were mapped as a single patch. Plants more than one meter from other plants were mapped 

individually. The height of growing shoots was measured at five locations within each site and the 

number of shoots growing within five randomly placed 1-m 2 quadrats was counted at each site. 

Quadrats that fell within a bare spot between plants mapped as a patch were recorded as zeros and 

factored into the site average. 

A photo of each cordgrass transplant site was taken from the west end of the transplant transect 

looking roughly eastward. These photos will later be compared to photos taken from the same points 

during the next annual survey in August 2009. 

Salt Marsh Transect Monitoring 

Nineteen permanent vegetation transects were established in 2008 at Bolsa Chica: three at Rabbit 

Island, four on the east and north shore of the FTB, three in the west MTB, three in the central MTB, 

three in the east MTB, and 3 in the Muted Pocket Marsh (Figure 1-2). The 50-meter transects were 

positioned to characterize a range of elevations within the marsh and the endpoints each marked with 

labeled stakes and recorded using a dGPS. The coordinates for the transect endpoints are listed in 

Appendix 1-B. 

On August 14 and 21, 2008, each transect was surveyed by stretching a 

fiberglass measuring tape between the stakes and using a line-intercept 

method to document the percent cover of plant species and bare 

ground/open water. The presence of individual plant species was 

recorded for each meter along the 50-meter transect, including a notation 

of which species was dominant if there were multiple species. Plants and 

bare ground/open water were recorded only if a part of the plant or bare 

space fell underneath the vertical plane of the measuring tape. 

Additionally, a list of all species observed on each transect within one 

meter on either side of the transect was recorded. The canopy height was 

recorded at five points randomly selected along each transect and a 

photograph of each transect was taken from a fixed point to allow direct 

non-quantitative comparison of change over time when repeat photos are 

taken in subsequent years. 

Transect monitoring. 

The collected data were assessed to determine the percent cover of native and non-native species, both 

with and without overlap, on each transect within each survey area. The presence of multiple species 


C B A 

MPM 2 

CBA 

C 

B 

A 

MPM 3 

Muted Pocket Marsh 

MPM 1 

A B C 

A 

B 

C 

FTB North 

WMTB 3 

West Muted 

Tidal Basin C 

BA 

WMTB 1 

B 

A 

C 

WMTB 2 

Central Muted 

Tidal Basin 

RI 1 

B 

A 

C 

RI 2 

A 

B 

C 

RI 3 

Rabbit 

Island 

C 

B 

A 

FTB E3 

CMTB 2 

C 

B 

A 

C BA 

C 

B 

A 

C BA 

CMTB 3 

FTB E2 

CMTB 1 

C 

B 

A 

EMTB 1 

East Muted 

Tidal Basin 

C 

B 

A 

EMTB 2 

C 

B 

A 

EMTB 3 

FTB E1 

C BA 

C B A 


Vegetation Transects 

Soil Collection 

0 100 200 400 600 

Meters 

Vegetation and soil monitoring locations 


Figure 1-2 




within the plant canopy often resulted in the total percent cover exceeding 100%. The percent cover 

excluding overlap was determined by considering only the dominant plant species for each transect. 

Results 

Habitat Mapping 

Ten vegetated and seven non-vegetated habitats were mapped within the 402-ha (994-acre) study area 

in 2008. Vegetated habitats included southern coastal salt marsh, disturbed coastal salt marsh, 

cordgrass, mule fat scrub, coastal sage scrub, coastal and valley freshwater marsh, southern arroyo 

willow riparian forest, eelgrass, decaying/transitional vegetation, and non-native vegetation. Although 

cordgrass is a component of southern coastal salt marsh, it was mapped separately to track its spread 

throughout the site. Non-vegetated habitats included: salt panne, disturbed salt panne, intertidal sand 

shoal, intertidal mudflat, open water, unvegetated nest site, and urban/developed. Figure 1-3 presents 

the habitats mapped on-site, and Table 1-1 summarizes the acreage of each. The following text 

describes each habitat in detail. 

Table 1-1. Area of habitats within the Bolsa Chica study area (May 2008). 

Habitat Hectares Acres 

Southern coastal salt marsh 92.0 227.2 

Disturbed southern coastal salt marsh* 7.1 17.5 

Cordgrass*

0 250 500 1,000 

Meters 

Habitat Type 

Southern coastal salt marsh 

Disturbed southern coastal salt marsh 

Cordgrass 

Mule fat scrub 

Coastal sage scrub 

Coastal and valley freshwater marsh 

Southern arroyo willow riparian forest 

Eelgrass 

Decaying/transitional vegetation 

Non-native vegetation 

Salt panne 

Disturbed salt panne 

Intertidal sand shoal 

Intertidal mudflat 

Open water 

Unvegetated nest site 

Urban/developed 

Habitat Map - May 2008 


Figure 1-3 




central and east MTBs) are species that are tolerant of highly saline soils. This relictual marsh is 

almost entirely composed of large expanses of pickleweed (Sarcocornia pacifica and Arthrocnemum 

subterminale). The pickleweed quality varies throughout the site from tall and robust, to short in 

stature and desiccated. Other species common in the salt marsh in low densities included: salt grass 

(Distichlis spicata), saltwort (Batis maritima), and alkali heath (Frankenia salina). 

The majority of this salt marsh habitat is of moderate quality based on its fairly expansive nature, 

isolation from human disturbance, and limited infestation by exotic and upland species. While there is 

low plant diversity within this habitat, such conditions are normal for coastal salt marsh habitats and 

especially so for non-tidal marshes that experience hypersaline sediment conditions and the 

environmental extremes of wet and dry seasons and years. 

More functional coastal salt marsh habitat is now present in the FTB (on Rabbit Island) and Muted 

Pocket Marsh, both of which received daily tidal flushing following the restoration completion. 

Additionally, in March 2008 the west MTB was opened to muted influence from the FTB, with the salt 

marsh receiving daily tidal flushing for the first time in many decades. This resulted in the inundation 

of large areas of pickleweed for some or nearly all of each day. In some areas the inundation 

frequency may be greater than the tolerance of the pickleweed; those areas are expected to convert to 

open mudflat in future years. 

As noted above, cordgrass was not included in the coastal salt marsh mapping in order to better track 

its spread over time. 

Disturbed Southern Coastal Salt Marsh 

This habitat category was used to distinguish areas of 

southern coastal salt marsh that were degraded due 

primarily to disturbance by heavy equipment and 

vehicles associated with both the construction elements 

of the restoration program and the on-going 

contamination remediation activities within the oil field. 

This category was also used for the unvegetated sidecast 

piles of sediment place on either side of the channels 

that were dug out of the marsh as part of the restoration 

of the MTBs. These will be re-categorized in future 

assessments if salt marsh vegetation becomes reestablished. 

Sidecast mounds remaining from channel excavation. 

Cordgrass 

New cordgrass growth with flowers. 

One year post-transplant, 196 m 2 of cordgrass was mapped at 10 

of the 14 transplant sites (Figure 1-4). At most locations 

cordgrass was present in only portions of the original transplant 

site, and in some cases had spread laterally some distance out of 

the site. Within plots of cordgrass the shoot density ranged from 

2 to 98 shoots/m 2 , with a mean of 23 shoots/m 2 . The canopy 

height ranged from 9 to 85 cm, with a mean of 52 cm. Nearly all 

cordgrass was flowering, with seeds seen scattered on the mudflat 

around the plants. 


August 22, 2007 cordgrass transplant sites - 0.3 hectare (0.7 acre) 

8 

9 

August 21, 2008 cordgrass distribution - 0.02 hectare (0.05 acre) 

Numbers are transplant IDs 

7 

11 10 1 

12 

6 

5 

4 

3 

2 

13 

14 

0 200 400 800 

Meters 

Full Tidal Basin cordgrass distribution 


Figure 1-4 




Transplant site 6 may have belowground rhizomes that will persist and support new growth in the 

future. Sites 11, 12, and 13 are not expected to recover because they are at a slightly lower elevation 

than the other sites. Photos taken of each transplant site are presented in Appendix 1-C along with the 

mean shoot density and mean canopy height at each. Photos of Sites 12 and 13 are included. 

Mule Fat Scrub 

Mule fat scrub occurs primarily in the southeast portion of the Seasonal Ponds, where perennial 

freshwater input supports several freshwater vegetation communities, and sporadically along the 

eastern boundaries of the study area near other sources of freshwater. This habitat is nearly monotypic 

mule fat (Baccharis salicifolia). 

Coastal Sage Scrub 

Baccharis scrub occurring within the project site was mapped as coastal sage scrub. This habitat is 

composed almost entirely of coyote brush (Baccharis pilularis) and Emory’s Baccharis (Baccharis 

emoryi) various non-native weeds such as radish (Raphanus sativus) and black mustard (Brassica 

nigra). Baccharis scrub is a sub-class of coastal sage scrub that is generally almost entirely dominated 

by coyote brush and is typically indicative of greater soil disturbance, higher moisture levels, and/or 

sandier soils. This vegetation occurs near the more highly disturbed eastern boundary of the study 

area, however it was mapped in such limited areas that it is not visible on the habitat map. 

Coastal and Valley Freshwater Marsh 

A few small areas of coastal and valley freshwater marsh were mapped in the southeast corner of the 

seasonal ponds. The freshwater marsh is composed primarily of broad-leaved cattail (Typha latifolia) 

and narrow-leaf cattail (Typha angustifolia), with occasional California bulrush (Scirpus californicus) 

and prairie bulrush (Scirpus robustus) nearby. These small freshwater marshes persist on the margins 

of the coastal salt marsh due to perennial freshwater input as both surface runoff and groundwater 

seepage from adjacent lands. 

Southern Arroyo Willow Riparian Forest 

A single mature stand of arroyo willow (Salix lasiolepis) occurs adjacent to the freshwater marsh and 

mule fat scrub in the southeastern portion of the Seasonal Ponds. This willow stand receives high 

amounts of seepage from the adjacent bluff as well as surface runoff sources and has a small drainage 

running through it out onto the salt panne. 

Eelgrass 

Eleven months post-transplant, 0.8 ha (2.0 acres) of eelgrass 

was mapped in the FTB on June 30, 2008, marking a 

doubling in area from the 0.4 ha (0.9 acre) of eelgrass 

originally transplanted in 2007. (Figure 1-5). Eelgrass had 

persisted at 13 of the original 15 transplant sites and spread 

extensively into the southern portions of the basin. The two 

transplant sites that were positioned in the center of the basin 

did not appear to have persisted through to the June 2008 

survey. Due to the increasing tidal muting of the FTB in 

2008, eelgrass was able to establish at higher elevations than 

it typically would, often growing at the base of the riprap in 

the outer portions of the FTB. 

Eelgrass in the FTB. 


August 24, 2007 eelgrass transplant sites - 0.3 hectare (0.8 acre) 

June 30, 2008 eelgrass distribution - 0.8 hectare (2.0 acres) 

0 200 400 800 

Meters 

Full Tidal Basin eelgrass distribution 


Figure 1-5 




Decaying/Transitional Vegetation 

This habitat was used to describe transitional vegetation communities exhibiting the effects of 

exposure to or inundation by regular tidal influence following long periods of freshwater influence or 

intermittent inundation. This included rampikes of dead eucalyptus and Myoporum trees that ring the 

Muted Pocket Marsh and presently provide roosting and perching habitat for a variety of birds. These 

trees will eventually decay and begin to fall into the marsh. This category was also used to describe 

large areas of Rabbit Island. Prior to the opening of the FTB to the ocean, Rabbit Island supported 

mostly non-native upland species at the highest elevations and was ringed by coastal salt marsh. 

Following the introduction of tidal influence, which at extreme tide submerges much of Rabbit Island, 

both the upland and salt marsh vegetation began to die. Much of Rabbit Island is now covered with the 

standing dead woody stalks of past marsh and upland vegetation, including broad expanses of dead 

hottentot fig (Carpobrotus edulis). It is anticipated that as the decaying vegetation decomposes, 

coastal salt marsh will gradually become established at the mid- to high salt marsh elevations and 

cordgrass and mudflats will dominate the lower marsh elevations. 

Decaying marsh and hottentot fig on Rabbit Island (left/center), dead salt marsh transitioning to mud flat following inundation of the west MTB (right). 

Small losses to salt marsh in the MTBs and Seasonal Ponds were mapped as decaying vegetation as 

well, due to prolonged inundation by tidal waters or seasonal freshwater ponding. This process had 

only begun in the MTBs and is expected to results in greater losses of marsh in the coming years as the 

MTBs are all opened to tidal influence. 

Non-Native Vegetation 

Non-native vegetation was mapped primarily on the eastern boundaries of the study area in association 

with various oil filed operations and staging areas, as well as residential areas that contribute escaped 

landscape plantings. Common species include: radish, black mustard, castor-bean (Ricinus communis), 

myoporum (Myoporum laetum), hottentot fig, and tumbleweed (Amaranthus albus). Notably, there is 

little to no occurrence of the highly invasive non-natives giant reed (Arundo donax) or pampas grass 

(Cortaderia selloana) within the study area. By May 2008 non-native vegetation, primarily hottentot 

fig and slender-leaved iceplant (Mesembryanthemum nodiflorum), had begun to colonize the created 

nest sites. Only areas that were infested to a high enough degree as to preclude nesting were mapped 

as non-native vegetation, however there was a regular scattering of these and some native species on 

the surface of all three nest sites. 

The areas immediately adjacent to the roads bordering the marshes often supported a narrow mix of 

roadside weeds and a few native species such as goldenbush (Isocoma menziesii). Unless these weed 

bands were more than about 3 m wide and monotypically non-native, these roadside areas were not 

called out as a distinct habitat, rather included in either the coastal salt marsh they were mixed with or 

the urban/developed road, as appropriate. 




Salt Panne 

Salt panne in the Seasonal Ponds. 

The habitat covering the third largest area within the study area 

was unvegetated salt panne, primarily in the Seasonal Pond and 

Future Full Tidal Basin areas. These areas were historically 

subsided marsh plain inundated by seawater, but are currently 

inundated intermittently by primarily freshwater. These low 

permeability areas collect water during rainy months, and later 

dry by evaporation as conditions warm in spring and summer 

months. This leaves hypersaline conditions that are 

inhospitable to most marsh plants. Although pickleweed has 

colonized much of the salt panne areas or its margins, the areas 

lowest in elevation that pool water for extended periods remain 

unvegetated. 

Disturbed Salt Panne 

Due to the use of the salt panne habitat by various migratory birds, 

including western snowy plovers for nesting, it is relevant to call 

out large areas of salt panne that are disturbed. Generally, these 

areas are previously flat expanses that have been traversed by 

various trucks and equipment, primarily for contaminated sediment 

removal work. When disturbed during wet periods, this activity 

leaves the ground deeply rutted, less desirable to foraging and 

nesting birds, and of some concern in relation to harboring pests 

such as mosquitoes longer into the summer season. Disturbed salt 

panned made up only 3% of the total salt panne area. 

Disturbed salt panne in the Seasonal Ponds. 

Intertidal Sand Shoal 

This category refers to the depositional flood shoals present in the FTB inlet. The shoals were 

composed of unvegetated and unconsolidated sand that can be highly transitory in nature as they are 

chronically accreted and reworked by the tides and waves. Their mapped extent was fully dependent 

on the tidal elevation at the time of the aerial imagery collection. A more comprehensive assessment 

of the shoal is included in the bathymetric monitoring section of this report (see Section 2.2). 

Intertidal Mudflat 

This habitat included the unvegetated intertidal mudflats occurring below elevations at which vascular 

plant communities occur. This habitat occurred primarily on the borders of FTB, in portions of the 

Muted Pocket Marsh, and at the lower elevations of Rabbit Island where inundated salt marsh 

transitioned to mudflat after the opening of the inlet. Although the cordgrass bench on the east shore 

of the FTB is above the typical intertidal mudflat zone, it will also be mapped as intertidal mudflat 

until such time as marsh vegetation develops. 

Open Water 

Open water habitat included all tidal waters, all permanently inundated areas in the FTB, Muted Pocket 

Marsh, and Freeman Creek. Standing water in the Seasonal Ponds and FFTB areas were mapped as 

salt panne in consideration of their underlying, persistent substrate. This habitat covered the greatest 

acreage in 2008, due to the large expanses of open water in the FTB. As with mudflat and sand shoal, 

its mapped extent was dependent on the tidal elevation at the time of the aerial imagery collection. In 




years of greater tidal muting, the open water areas will be slightly larger, since the low tides won’t fall 

to as low an elevation as they would immediately following a dredge event, when tidal muting is 

minimized. 

Unvegetated Nest Site 

This includes Nest Sites 1, 2, & 3. They are topped with sand and groomed to appeal to targeted 

sensitive avian species that nest on such sites. Portions of the nest sites that have non-native vegetation 

growing at a high enough density as to preclude nesting by the targeted species were excluded from the 

total nest site area calculations and mapping instead as non-native vegetation. 

Urban/Developed 

The areas designated as urban/developed were comprised of paved streets, paved and unpaved oil field 

roadways and berm roads, recreational paths, oil pads, or highly disturbed areas adjacent to the 

residential neighborhoods or related to oil field operations and contamination remediation. 

Salt Marsh Transect Monitoring 

The results of the transect monitoring are presented in Table 1-2. At the bottom the table is a summary 

of the percent vegetative cover on each transect, disregarding any overlap of species, for all vegetation 

and for native species only. Summaries are also provided for native and non-native species, 

accounting for overlapping species within the transect. Figure 1-6 presents the mean coverage of 

native and non-native species at each of the five survey areas, allowing for overlap of species. The 

MPM had very little non-native cover and the FTB transects had none, however it should be noted that 

Rabbit Island, which is also located in the FTB, did have non-native species. The FTB transects are all 

located on the intertidal mudflats of the north and east shore, where conditions are unfavorable for the 

establishment of most non-native species due to regular tidal inundation. The non-native species at 

Rabbit Island occur at elevations above the highest high tides. 

100 

Mean % cover 

80 

60 

40 

20 

Native Vegetation 

Non-native Vegetation 

0 

Rabbit Island Full Tidal Basin West MTB Central MTB East MTB Muted Pocket 

Marsh 

Figure 1-6. Mean percent cover (including overlap) of native and non-native vegetation by survey area (2008) 

The most abundant non-native species were the iceplants M. nodiflorum and C. edulis, with M. 

nodiflorum particularly abundant in the non-tidal portions of the central and east MTBs. The iceplant 

remaining in the west MTB was showing signs of stress from the introduction of tidal influence in 

March and will likely die in the coming year. 



Table 1-2. Vegetation transect monitoring results (2008). 

Plant Species Observed Along Transects 

Percent Cover 

Scientific Name Common Name RI 1 RI 2 RI 3 FTB N FTB E1 FTB E2 FTB E3 WMTB 1 WMTB 2 WMTB 3 CMTB 1 CMTB 2 CMTB 3 EMTB 1 EMTB 2 EMTB 3 MPM 1 MPM 2 MPM 3 

Native Species 

Sarcocornia pacifica Pacific pickleweed 14 50 32 10 8 100 36 88 48 76 28 82 74 42 16 4 

Arthrocnemum subterminale Parish’s pickleweed 2 2 8 

Distichlis spicata Saltgrass 26 4 26 58 6 76 14 6 4 4 

Frankenia salina Alkali heath 2 6 2 10 4 4 8 34 4 24 

Monanthochloe littoralis Shoregrass 14 

Cressa truxillensis Alkali weed 12 18 4 

Suaeda esteroa Estuary seablite 12 4 

Batis maritima Saltwort 26 12 2 

Limonium californicum Western marsh rosemary 2 

Juncus acutus ssp. leopoldii Southwestern spiny rush 6 2 

Atriplex prostrata Spearscale 2 

Atriplex canescens var. canescens Four wing saltbush 12 

Ruppia maritima Wigeon grass 18 26 36 

Enteromorpha sp. (alga) Sea lettuce 2 6 

Non-native Species 

Mesembryanthemum nodiflorum Slender-leaved iceplant 16 2 18 4 8 

Bassia hyssopifolia Five hook bassia 18 12 12 8 2 2 

Salsola tragus Russian thistle 4 

Carpobrotus edulis Hottentot-fig 12 6 6 6 

Polypogon monspeliensis Annual beard grass 6 2 

Bromus madritensis rubens Red brome 2 

Dead plant debris 14 2 14 14 10 4 4 8 18 

Bare construction sidecast 8 12 10 8 

Open water 4 4 2 34 

Bare ground /mudflat 30 18 10 90 82 72 58 2 32 46 2 6 16 14 

Total Percent Vegetative Cover Without Overlap (all species) 58 80 76 10 18 28 42 82 100 94 100 58 88 34 88 84 100 42 34 

Total Percent Native Vegetative Cover Without Overlap 46 58 62 10 18 28 42 56 100 94 90 52 66 30 88 76 30 88 76 

Total Percent Native Vegetative Cover With Overlap 50 62 78 10 18 28 42 68 106 124 106 54 80 32 102 92 124 46 36 

Total Percent Non-native Vegetative Cover With Overlap 12 22 18 0 0 0 0 28 0 0 18 8 26 4 0 8 2 0 0 

Total Number of Native Species within 1 m of Transect 5 6 5 1 1 2 2 4 3 4 3 2 3 2 3 3 9 6 6 

Total Number of Non-native Species within 1 m of Transect 2 3 2 0 0 0 0 4 0 0 5 6 4 1 2 2 1 0 0 

Mean Canopy Height (cm) 26 44 N/C 28 0 0 0 36 25 52 45 50 33 26 46 22 41 30 25 




Table 1-2 also summarizes the total number of native and non-native species found within one meter 

on either side of the transect line. The salt marsh in the MPM was by far the most diverse of all the 

areas surveyed, followed by Rabbit Island. One species was found in the 2-m belt that was not 

detected on any transect: western sea purslane (Sesuvium verrucosum) along transect MPM2. As noted 

above the marshes in the MTBs are low in diversity, supporting primarily S. pacifica and D. spicata. 

The FTB transects were primarily unvegetated in 2008, with the exception of a small amount of S. 

pacifica becoming established at the north end of the basin at FTB North and considerable growth of 

R. maritima on the intertidal mudflats on the east shore of the FTB. 

Although not captured in the transect monitoring, there was a narrow band of S. pacifica seedlings that 

had established on the large mudflats of the eastern shore of the FTB (cordgrass bench) near the base 

of the riprap. In some cases the pickleweed extended out as far as 30 m onto the mudflat from the 

riprap. Also of note, though not captured in the transect monitoring, was the persistence of the rare 

coastal dune plant coast woolly heads (Nemacaulis denudata var. denudata) on Rabbit Island. The 

restoration project aimed to protect this species at the highest elevations of Rabbit Island through 

removal of hottentot fig during the project and by preserving the dune areas about the highest tides in 

the project design. A comprehensive survey for this species was not conducted, however four patches 

covering approximately 50m 2 in total were mapped incidentally during the survey work on the island. 

Hottentot fig was encroaching on the remaining patches of woolly heads and immediate intervention 

through removal of the non-native will be critical to the survival of woolly heads at Bolsa Chica. 

The scars from the construction grading of the cordgrass bench were still evident in 2008 and created 

pools of standing water at low tide, which had heavy growth of R. maritima in them. An interesting 

observation was made by Peter Knapp of a snowy plover foraging for small fish in these pools, an 

unusual behavior for this bird. The bench showed signs of growing maturity with the natural 

development of tidal channels at the edges of the bench. 

Pickleweed seedlings, Ruppia maritima, and channel development on the mudflats of the eastern shore of the FTB. 

The photos taken at each of the nineteen transects will be presented following the next monitoring 

event in series to illustrate change over time. 

Discussion 

The 2008 vegetation monitoring at Bolsa Chica was the first full monitoring event to document habitat 

distribution and species composition following the restoration. Coastal salt marsh was the most 

abundant vegetated habitat and changes in its distribution will be tracked in the coming years, since its 

availability is critical for nesting by Belding’s Savannah sparrow. In 2008, only the west MTB was 

open to tidal influence and the marsh had had limited time to respond prior to the monitoring. It is 




anticipated that this basin and the central and east MTBs will have shifts in marsh distribution in the 

coming years as all basins are opened to the FTB. The lowest lying areas will be converted to open 

water and mudflat, while marsh will be able to expand into areas previously dominated by non-native 

weeds once they are eliminated by the salt water influence. The MTBs were designed to support 51.1 

ha (126.3 acres) of salt marsh habitat. In 2008 the three basins had a total of 49.8 ha (122.9 acres) of 

coastal salt marsh and disturbed coastal salt marsh. 

An unanticipated benefit of the restoration work in the 

MTBs was the placement of the sidecast excavated 

material from tidal channel creation (described above as 

disturbed coastal salt marsh). These mounds have been 

smoothed by weather and standing water in most areas 

and are gradually becoming vegetated at their base with 

pickleweed. The elevated mounds serve as a refuge from 

tidal inundation and are heavily used at high tide or 

during periods of heavy rainfall accumulation by loafing 

shorebirds. They are also used by Belding’s Savannah 

sparrow’s as elevated perch points, and as they become 

vegetated will likely provide additional nesting habitat at 

Hundreds of shorebirds loafing on sediment mounds 

in flooded marsh in the central MTB. 

elevations safe from tidal inundation. Their vegetation by salt marsh will also help to offset losses of 

pickleweed at lower elevations due to the introduction of tidal influence. Because these mounds are 

comprised only of the sidecast material from channel excavations, they do not have a consequential 

effect on the hydrology of the MTBs, but add a valuable habitat element. 

Salt marsh distribution is also expected to change on Rabbit Island as low-lying marsh continues to 

convert to mudflat. The FTB was designed to eventually support 7.7ha (19.1 acres) of pickleweed. In 

2008, approximately 4.9 ha (12.4 acres) of coastal salt marsh were present in the basin, including 

Rabbit Island. Salt marsh will be gained at the higher elevations as non-native vegetation continues to 

convert to mid and high marsh. Pickleweed on the cordgrass bench in the FTB may continue to fill in 

along the base of the riprap in the coming years as well. 

The transplant of cordgrass in the FTB was intended to accelerate the development of low salt marsh 

habitat, with the goal of providing suitable habitat for light-footed clapper rails (Rallus longirostris 

levipes). In 2008, one year post-transplant, the majority of the transplant sites had persisted. By 

December 2007, four months post-transplant, most of the planted shoots had senesced and fallen over, 

so all shoots mapped and measured in 2008 were new growth. Although only 196 m 2 of cordgrass 

were mapped in 2008 (in comparison to the 3,000 m 2 area that was planted), the cordgrass had 

expanded within each transplant to become denser, and was healthy, flowering, and dispersing seed. 

The slow establishment is typical of cordgrass transplants, but may have been exacerbated by the 

prolonged inundation periods that resulted from tidal muting as the flood shoal in the FTB inlet 

increased in size, restricting low tide drainage (see Appendix 2-A). Dredging scheduled for January 

2009 will improve tidal range and reduce inundation periods at the elevations where the cordgrass was 

planted. It is likely that cordgrass at slightly higher elevations on the cordgrass bench will be more 

successful. Based on the establishment and expansion rates seen in a similar transplant conducted at 

Batiquitos Lagoon, it is expected that the cordgrass will begin to form continuous patches suitable as 

habitat within four to five years of transplant (M&A 2009). 




It was interesting to note during the avian surveys throughout the year that large shorebirds showed a 

clear preference for foraging and loafing on portions of the mudflat where cordgrass was growing. 

There are other locations within the restoration area that are suitable for cordgrass establishment and 

should be the focus of future transplants, particularly around the west and south side of Rabbit Island 

and in the MTBs. Cordgrass establishment on the shores of NS 1 on the west side of the FTB is not 

desirable, because clear access from the nest site to the shoreline should be maintained for snowy 

plovers. 

Another habitat goal of the restoration was the establishment of eelgrass in the FTB. The 2007 

transplant was successful, with a doubling of the area covered after one year. The eelgrass began 

flowering shortly after transplant, which was likely the source of its spread to areas nearly a kilometer 

from the transplant sites. During 2008, eelgrass may have been able to extend to higher elevations in 

the basin due to the tidal muting and resulting higher low tides. The eelgrass may recede from these 

upper elevations in 2009 and 2010 following maintenance dredging to restore lower low tide 

conditions. These losses will be more than offset by the large increases in distribution that are 

anticipated in the coming years, with the most dense and expansive growth occurring in the mid and 

lower portions of the FTB. 

The next full vegetation monitoring event, including aerial photography, habitat mapping, and transect 

surveys, will be conducted in summer 2011 (Year 5) as called for in the Monitoring Plan. Additional 

photography and habitat mapping will be done in 2009 to document interim conditions. 


• Continue collection of aerial imagery each year (rather than in Years 2, 5, and 10 only) to track 

changes in water levels, site conditions, and habitat development. 

• Consider adding species diversity to the Bolsa Chica system by transplants from other areas such 

as Upper Newport Bay or Outer Bolsa Bay. 

• Consider opportunities for introduction of Salt Marsh Bird’s Beak (Cordylanthus maritimus) from 

Upper Newport Bay into areas of Freeman Creek, the Seasonal Ponds, and the Muted Tidal Basins, 

where seasonally lowered salinities would promote seed germination. 

1.2. SOILS/SEDIMENT MONITORING 

Introduction 

The Monitoring Plan anticipated that soil and sediment conditions throughout the restored portions of 

Bolsa Chica might be changed in the course of dredging and/or introduction of tidal flushing. 

Monitoring was developed to document the soil conditions in the restored areas as new vegetation 

colonized and existing vegetation adjusted to the restoration of tidal influence. 

The Monitoring Plan calls for soils monitoring to be initiated in Year 2 of the program, coinciding with 

the vegetation monitoring task described in the previous section. 




Methodology 

Soils monitoring was conducted on September 30 and October 2, 2008 in conjunction with the 

vegetation monitoring work. Soil samples were collected along each vegetation transect, at three 

locations distributed along the elevation range of each transect. The samples were generally collected 

at each end of the transect and at a mid-point along the transect that represented a median elevation and 

were assigned a label of A, B, and C (Figure 1-2). 

At each sampling point soil, small holes were dug to a depth of 5 

and 15 centimeters to assess the pore water quality. Most holes 

filled with pore water after being dug, which was measured for 

salinity with a hand-held refractometer to the nearest part per 

thousand (ppt) and for pH with a Hanna HI 9125 portable pH 

meter inserted into the pore water. If the holes formed no 

pooled water, interstitial soil water was filtered from the soil 

using a syringe containing two No. 1 filter papers. Filtered 

water was placed onto a refractometer and the salinity recorded. 

If the sampling point along the transect occurred over open 

water, the open water salinity and pH was measured instead. 

Soil and pore water collection. 

At the same locations, sediment samples were collected from the surface (upper 5 cm) and transported 

to the laboratory for analysis of grain size distribution (ASTM D4464) and total organic carbon (TOC) 

(EPA 9060A). 

Results 

The results of the soil assessment are presented in Table 1-3. In many cases the soil was so dry 

(generally in sandy areas) it was not possible to extract water from the sample to make the field 

measurement of pH or salinity. In some cases salinity could be measured while pH could not, because 

only a few drops of water are needed to determine salinity, whereas the pH meter needs pooled water 

to submerge the probe in. The table presents the mean grain size description for each sample; the full 

grain size analyses for each sample are presented in Table 1-4. 

TOC was highest in silty, vegetated areas, particularly in the Muted Pocket Marsh, which has a more 

mature, dense, and diverse salt marsh than the other areas. Pore water pH in vegetated marsh was 

generally in the 6 to 7 range, while the pH of areas inundated with tidal waters was around 8.3 

generally. The only low pH (5.3) was measured in a basin of pooled water at CMTB 3A that had a 

high iron content (the water and sediment were rusty red). Pore water salinity was highly variable 

depending on its degree of exposure to tidal waters, elevation, and surrounding sediment grain size. 

Discussion 

The Monitoring Plan discusses that a knowledge of soil conditions will help determine which factors 

might be controlling plant community diversity and productivity, and which types of plant 

communities are likely to develop in the future. Although the plant diversity was documented in the 

transect monitoring described above, it was generally very low or absent (in areas that had yet to be 

colonized by vegetation). It is therefore difficult to seek correlations between marsh diversity and soil 

characteristics at this early stage of marsh development. The present diversity of the marsh is likely 

related to the length of time the marsh has been isolated from tidal influence and the degree to which 

opportunitistic introduction of new marsh species has occurred. 




Table 1-3. Soils monitoring results (September 2008). 

RABBIT ISLAND 

northwest portion of FTB, 

lower portions intertidal 

FULL TIDAL BASIN 

open to ocean 

WEST MUTED TIDAL 

BASIN 

open to FTB 

CENTRAL MUTED TIDAL 

BASIN 

closed to FTB but flooded by 

leaked seawater 

EAST MUTED TIDAL BASIN 

closed to FTB, but water in low 

areas 

MUTED POCKET MARSH 

intertidal through culverts to 

Outer Bolsa Bay (not FTB) 

Transect Rep 

Total Organic 

Carbon 

(mg/kg) 

Mean Grain 

Size Description 

Pore Water 

pH 

5cm deep 

Pore Water 

pH 

15cm deep 

Pore Water 

Salinity (ppt) 

5cm deep 

Pore Water 


15cm deep 

Notes 

RI1 A 4,400 Fine Sand N/M N/M N/M N/M dry, Sarcocornia, iceplant 

B 1,400 Fine Sand N/M N/M N/M N/M dry, Distichlis, Sarcocornia 

C 14,000 Fine Sand 7.98 7.98 35 35 underwater, algal mat 

RI2 A 9,400 Fine Sand 6.75 6.75 45 40 Sarcocornia 

B 16,000 Fine Sand N/M N/M N/M N/M dry 

C 16,000 Fine Sand 6.92 7.17 50 49 mudflat 

RI3 A 15,000 Fine Sand N/M N/M 35 42 

B 26,000 Fine Sand N/M N/M N/M N/M Sarc, Distichlis, high point sand dune 

C 15,000 Fine Sand N/M N/M 39 N/M 

FTB North A 3,400 Fine Sand N/M N/M N/M N/M bare, fluffy levee dirt 

B 1,700 Silt N/M N/M N/M N/M no veg, in clay layer 

C 2,100 Fine Sand N/M N/M 65 65 on mudflat in pickleweed 

FTB E1 A 2,900 Fine Sand 8.34 8.34 35 35 underwater, water measured 

B 4,200 Fine Sand 8.34 8.34 35 35 underwater, water measured 

C 5,800 Fine Sand 8.34 8.34 35 35 underwater, water measured 







WMTB 1 A 15,000 Silt N/M N/M > 100 > 100 damp, iceplants 

B 12,000 Silt 8.17 8.17 50 50 all Distichlis, underwater, water measured 

C 18,000 Silt 6.64 6.64 60 55 saturated 

WMTB 2 A 22,000 Fine Sand 8.43 8.43 40 40 underwater, water meas, submerged Sarc 

B 33,000 Fine Sand 8.37 8.37 40 40 underwater, water meas, submerged Sarc 

C 13,000 Silt 8.40 8.40 40 40 underwater, water meas, submerged Sarc 

WMTB 3 A 19,000 Fine Sand 7.85 7.85 39 39 underwater 

B 21,000 Silt 8.82 8.82 35 35 underwater in Distichlis 

C 13,000 Silt 8.67 8.67 36 36 underwater in Distichlis 

CMTB 1 A 11,000 Fine Sand 7.38 6.66 100 80 saturated, sampled water pooled in holes 

B 29,000 Fine Sand N/M 6.86 70 65 very damp marsh 

C 18,000 Silt 7.88 7.88 72 72 underwater, water meas, submerged Sarc 

CMTB 2 A 19,000 Silt 6.65 6.53 50 50 no veg 

B 23,000 Fine Sand 6.79 6.79 52 52 underwater, water meas, submerged Sarc 

C 20,000 Silt 6.20 6.23 72 58 dead iceplant 

CMTB 3 A 3,200 Fine Sand 5.47 5.33 > 100 > 100 Red iron in H20 

B 4,100 Fine Sand N/M N/M N/M N/M Totally dry, no pore water 

C 6,400 Fine Sand N/M N/M > 100 N/M deep dry clay, poreH20 at surface 

EMTB 1 A 5,900 Silt N/M N/M 59 59 damp but no pooled water, syringed salin 

B 12,000 Silt N/M N/M N/M N/M dry, no pore water 

C 3,600 Silt 8.63 8.63 54 54 underwater, water measured 

EMTB 2 A 100,000 Silt N/M N/M N/M N/M dry, no pore water 

B 95,000 Silt N/M N/M N/M N/M damp but not wet enough to get water 


EMTB 3 A 6,900 Silt N/M N/M N/M N/M dry, no pore water 

B 61,000 Silt N/M N/M N/M N/M dry, no pore water 


PM1 A 12,000 Fine Sand N/M N/M 50 50 

B 23,000 Silt 6.87 N/M 40 38 

C 48,000 Silt N/M N/M 49 42 

PM2 A 44,000 Fine Sand N/M N/M 50 50 

B 60,000 Fine Sand 6.64 N/M 45 55 


PM3 A 36,000 Fine Sand N/M 6.65 40 40 

B 51,000 Silt 6.82 6.82 40 40 


N/M – not measured because soil was too dry to extract pore water. 




Table 1-4. Soil grain size analysis results (September 2008). 

Median 

Particle Size Distribution, wt. percent 

Silt 

Transect- Mean Grain Size Grain 

Sand Size 

& 

Replicate Description Size (mm) Gravel Coarse Medium Fine Silt Clay Clay 

RI 1-A Fine sand 0.235 0.00 0.00 15.26 80.94 3.06 0.74 3.80 

RI 1-B Fine sand 0.283 0.00 0.00 20.46 77.39 1.63 0.51 2.14 

RI 1-C Fine sand 0.251 0.00 0.00 20.72 68.35 9.35 1.58 10.93 

RI 2-A Fine sand 0.232 0.00 0.00 17.47 70.12 10.93 1.48 12.41 

RI 2-B Fine sand 0.253 0.00 0.00 14.53 80.55 3.96 0.96 4.92 

RI 2-C Fine sand 0.141 0.00 0.00 12.70 55.81 28.92 2.57 31.49 

RI 3-A Fine sand 0.251 0.00 0.00 18.74 73.99 6.43 0.84 7.27 

RI 3-B Fine sand 0.222 0.00 0.00 10.00 81.35 7.44 1.21 8.65 

RI 3-C Fine sand 0.229 0.00 0.00 12.62 79.01 7.18 1.20 8.38 

FTB NO-A Fine sand 0.100 0.00 0.00 4.67 53.34 34.01 7.98 41.99 

FTB NO-B Silt 0.046 0.00 0.00 0.00 36.99 52.38 10.63 63.01 

FTB NO-C Fine sand 0.098 0.00 0.00 3.37 57.48 33.36 5.79 39.15 

FTB E 1-A Fine sand 0.187 0.00 0.00 15.84 64.96 15.58 3.62 19.20 

FTB E 1-B Fine sand 0.071 0.00 0.00 5.92 43.05 41.76 9.26 51.03 

FTB E 1-C Fine sand 0.099 0.00 0.00 12.49 46.47 32.84 8.19 41.03 







WMTB 1-A Silt 0.032 0.00 0.00 8.53 24.18 51.28 16.01 67.29 

WMTB 1-B Silt 0.026 0.00 0.00 5.12 18.38 59.74 16.77 76.50 

WMTB 1-C Silt 0.022 0.00 0.00 3.15 17.08 61.71 18.05 79.77 

WMTB 2-A Fine sand 0.039 0.00 0.00 20.64 22.40 40.04 16.93 56.97 

WMTB 2-B Fine sand 0.029 0.00 0.00 11.22 23.73 47.66 17.39 65.05 

WMTB 2-C Silt 0.014 0.00 0.00 0.01 9.34 65.88 24.77 90.65 

WMTB 3-A Fine sand 0.105 0.00 0.00 25.81 29.53 34.87 9.79 44.66 

WMTB 3-B Silt 0.024 0.00 0.00 6.67 20.26 56.09 16.99 73.08 

WMTB 3-C Silt 0.019 0.00 0.00 5.82 17.89 57.38 18.90 76.29 

CMTB 1-A Fine sand 0.210 0.00 0.00 32.19 51.12 13.69 3.00 16.69 

CMTB 1-B Fine sand 0.128 0.00 0.00 22.57 39.23 31.44 6.76 38.20 

CMTB 1-C Silt 0.022 0.00 0.00 3.96 19.28 58.26 18.49 76.76 

CMTB 2-A Silt 0.030 0.00 0.00 8.91 22.56 53.03 15.50 68.53 


CMTB 2-C Silt 0.012 0.00 0.00 0.02 12.56 61.20 26.22 87.42 

CMTB 3-A Fine sand 0.092 0.00 0.00 6.37 50.58 33.76 9.29 43.05 


CMTB 3-C Fine sand 0.083 0.00 0.00 6.01 47.17 40.60 6.22 46.82 

EMTB 1-A Silt 0.057 0.00 0.00 5.07 33.93 55.13 5.87 61.00 

EMTB 1-B Silt 0.052 0.00 0.00 0.00 35.17 57.26 7.57 64.83 

EMTB 1-C Silt 0.041 0.00 0.00 0.00 25.22 65.67 9.11 74.78 

EMTB 2-A Silt 0.029 0.00 0.00 7.80 21.44 56.95 13.81 70.76 

EMTB 2-B Silt 0.022 0.00 0.00 2.71 15.77 65.64 15.89 81.52 

EMTB 2-C Silt 0.024 0.00 0.00 2.23 16.97 62.51 18.30 80.80 

EMTB 3-A Silt 0.043 0.00 0.00 0.00 35.58 50.66 13.76 64.42 

EMTB 3-B Silt 0.018 0.00 0.00 1.19 17.25 58.94 22.61 81.55 

EMTB 3-C Silt 0.022 0.00 0.00 2.71 18.94 59.33 19.03 78.35 

MPM 1-A Fine sand 0.109 0.00 0.00 14.24 45.47 32.45 7.84 40.29 

MPM 1-B Silt 0.022 0.00 0.00 2.85 22.14 56.22 18.78 75.00 

MPM 1-C Silt 0.036 0.00 0.00 3.75 33.52 49.62 13.11 62.73 

MPM 2-A Fine sand 0.073 0.00 0.00 8.42 40.96 43.30 7.31 50.62 

MPM 2-B Fine sand 0.098 0.00 0.00 3.25 60.64 30.54 5.57 36.11 

MPM 2-C Silt 0.037 0.00 0.00 3.26 23.52 59.70 13.51 73.21 

MPM 3-A Fine sand 0.051 0.00 0.00 14.73 27.61 48.21 9.45 57.66 

MPM 3-B Silt 0.037 0.00 0.00 8.50 25.15 54.38 11.97 66.35 

MPM 3-C Silt 0.024 0.00 0.00 2.60 16.72 63.34 17.34 80.68 




As the system continues to evolve it is expected that soil conditions may become more interesting and 

useful in understanding controls on vegetation structure or gaps within particular locations of interest. 

However, to adequately study the linkage between the development of new or restored marsh 

communities and the soil conditions, a much more focused study would be needed. While many 

interesting questions on the subject could be answered by more intensive studies, the present 

monitoring program does not substantially contribute to the larger objective of the present monitoring 

program, which is to document the habitat improvements achieved for wildlife by the restoration, to 

document the success of revegetation efforts, and to identify management needs to correct observed 

shortcomings in desired habitat development. 

Based on this circumstance, continued collection of soils data in Year 5, following the same 

monitoring structure, is not expected to yield substantial additional data for meeting the fundamental 

project goals. Therefore it is recommended that the collected soils data from 2008 serve as a baseline 

data set that can be revisited if future vegetation monitoring reveals any areas of concern, and that the 

Year 5 monitoring be removed from the program. If, after further vegetation development, particular 

areas of concerns exist regarding the absence of vegetation or undesirable vegetation conditions 

develop, a more focused soils investigation may be appropriate at that time. 


• Use collected soil data from 2008 as a baseline data set. 

• Remove Year 5 monitoring from the program. 

1.3. FISH COMMUNITY MONITORING 

Introduction 

The Monitoring Plan calls for fisheries monitoring to be conducted in Years 2, 5, and 10 following the 

opening of the FTB to the ocean. The Bolsa Chica Steering Committee decided to collect an additional 

year of data in Year 3 as well. The first sampling event of Year 2 was conducted during the prior 

reporting period, in October 2007. The remainder of the Year 2 monitoring and the first quarter of the 

Year 3 monitoring were conducted during the present reporting period (January to December 2008). 

Methodology 

Fisheries sampling was conducted over a two-day period each quarter to obtain the appropriate tidal 

elevations for each gear type. During 2008 surveys were conducted during daylight hours on January 

17 and 24, April 2 and 7, July 7 and 17, and October 15 and 27. Additional sampling in the MTBs was 

conducted on July 7 and November 24. Each quarter, sampling was done at Stations 1 and 2 in the 

FTB and in the Muted Pocket Marsh (MPM) (Figure 1-1). Limited sampling was done in the west 

MTB in April, July, and October after tidal waters had been introduced into the basin. 

Sampling equipment included an otter trawl, purse seine, and large beach seine at Stations 1 and 2 and 

a large beach seine only in the MPM. A variety of depth, current, substrate, and exposure conditions 

exist within each station, each of which encompass large areas. To characterize the fish communities 

that utilize the large sampling stations, three replicates hauls were made across each station, using gear 

as indicated in Figure 1-7. A small beach seine was used in the MTBs. 




The otter trawl consists of a 4.6-m trawl with 2-cm mesh in the body and 0.3-cm mesh in the cod end. 

The otter trawl was deployed at offshore sampling locations using a small vessel traveling between 1.5 

and 2 knots along 250-m transects. The trawl was used to sample primarily demersal offshore fish at 

Stations 1 and 2 in the FTB. The otter trawl was not used in the MPM due to the inaccessibility of the 

site by boat. 

The purse seine consists of a 66-m x 6-m seine with 1.2-cm mesh 

in the wings and 0.6-cm mesh in the bag. The purse seine was 

deployed at offshore sampling locations using a small vessel. 

This gear was used to sample adult and juvenile fish species in the 

water column as well as demersal fish at Stations 1 and 2 in the 

FTB. The purse seine was not used in the MPM due to the 

inaccessibility of the site by boat. 

Purse seine being deployed in the FTB. 

The large beach seine consists of a 15- m x 1.8-m net with a 1.8-m x 1.8-m x 1.8-m bag in the center. 

The seine has 1.2-centimeter (cm) mesh in the wings and 0.6-cm mesh in the bag. It was utilized to 

sample shoreline waters between the bottom and surface at depths of 0 to 1 m. The seine was 

positioned parallel to shore between 8 and 31 m from the water’s edge, depending on bottom contours. 

The seine was held in place for 3 minutes and then walked slowly to shore. 

Small beach seine in the West MTB. 

The small beach seine is a 7.3-m x 1.2 m-net with 0.3-cm mesh, with no 

bag. It was utilized to sample waters between 0-1 m in depth on the 

shorelines of the MTBs. The seine was positioned perpendicular to the 

shore, walked parallel to the shore for a measured distance, then pivoted 

in and walked to shore. The length of the each haul was determined by 

the space and water available at the time of the sampling and recorded 

on the field datasheet. 

By the October 2008 sampling period, the muting of the tide by the accreted flood shoal in the inlet 

had reduced the tidal drainage in the FTB to an extent that the regular shore-based large beach seine 

stations were deeper than suitable at some station replicates. At Station 1, replicate 2 had to be moved 

slightly to the west to an area that provided enough exposed beach to pull the net up onto. At Station 

2, replicate 1 had to be moved slightly to the west along the shoreline and replicate 3 moved around the 

corner to the north to accessed exposed beach as well. Station 2, replicate 1 was therefore not pulled 

through eelgrass beds during October 2008, while in all other quarters the eelgrass bed was sampled. 

In 2008, the MTB fish sampling program was not fully implemented because the basins were not fully 

open to the FTB through the tide gates at the water control structure (WCS). The west MTB was 

opened to FTB tidal influence in March 2008, therefore some sampling was done there in April 2008 at 

two locations near the tide gate. By July, some tidal water had spilled over from the west to the central 

MTB (as designed), so some sampling was done in that basin as well at two locations, though 

conditions were non-tidal. Additionally, the WCS was briefly opened to the FTB for several hours five 

days prior to the sampling, which likely allowed in some fish. In October, the west MTB was still the 

only basin open to tidal influence, however three replicate hauls were collected in both the west and 

central basins. 


BS PM Rep3 


BS PM Rep2 

STATION 1 

BS PM Rep1 

PS1 Rep1 

OT1 Rep1 

BS1 Rep1 

West Muted 

Tidal Basin 

SS WMTB Rep3 

SS WMTB Rep2 

SS WMTB Rep1 

Central Muted 

Tidal Basin 

SS CMTB Rep3 

OT1 Rep2 

BS1 Rep2 

PS1 Rep2 

SS CMTB Rep2 

SS CMTB Rep1 

BS1 Rep3 

PS1 Rep3 

East Muted 

Tidal Basin 

OT1 Rep3 


OT2 Rep1 

PS2 Rep1 

BS2 Rep1 

OT2 Rep2 

PS2 Rep2 

BS2 Rep2 

STATION 2 

OT2 Rep3 

BS2 Rep3 

PS2 Rep3 

Purse Seine 

Large Beach Seine (BS) 

Small Beach Seine (SS) 

Otter Trawl 

0 100 200 400 600 800 

Meters 

Fisheries sampling locations 


Figure 1-7 




All fish captured in the nets were transferred to buckets or tubs filled with seawater, worked up, and 

released. Data collected for fish caught in each haul included species identification, individual counts, 

standard length (in millimeters [mm]), and wet weight (in grams [g]). Ectoparasites, lesions, or 

tumors, if any, were also noted. Species that were not identified in the field were transported to the 

laboratory and identified utilizing field identification references and/or a dissecting microscope. All 

fish identifications were made using widely accepted field identification guides such as Miller and Lea 

(1972) and Eschmeyer et al. (1983). Fish nomenclature was standardized in conformance with Nelson 

et al. (2004). 

If more than 30 individuals of a species were caught in a replicate of any gear type, a batch sampling 

procedure was utilized. First, the standard length and weight was measured for 30 randomly selected 

individuals within the species. Second, the batch weight was measured for 100 additional randomly 

selected individuals. Finally, the total weight was measured for all of the remaining, uncounted 

individuals caught in the replicate. The number of uncounted individuals was then estimated using the 

batch weight of the 100 randomly selected individuals. 

All survey data were initially recorded in the field on hard copy data sheets and later transferred to a 

digital database and checked for accuracy. 

Due to the difficulty of rapidly and conclusively distinguishing between small arrow goby 

(Clevelandia ios) and shadow goby (Quietula y-cauda) in the field, gobies that may have belonged to 

either species were identified as "arrow/shadow goby complex". These functionally similar species 

commonly co-occur and occupy similar niches in the demersal fish community. Vouchers of the 

gobies collected were brought back to the lab for identification to document the actual species present 

at a given station. 

All macroinvertebrates captured in the fish sampling nets were collected, identified to the lowest 

taxonomic level possible, counted, and released. Due to the tremendous spatial variability of these 

species and the non-targeted methodology employed here to sample them, collected data were intended 

to generate a list of species that occur in the project area, rather than to provide definitive density and 

biomass data on their populations. The data are presented in the following section covering benthic 

invertebrates. 

At each study location, physical water quality parameters were measured coincident with the biological 

sampling described above. A Hydrolab Quanta ® multi-probe, calibrated in accordance with 

manufacturer specifications, was used to collect temperature, dissolved oxygen, turbidity, and salinity 

data. Readings were taken near the bottom and top of the water column. 

Results 

A total of 42 fish species were captured in 2008 quarterly fish sampling. The sampling results are 

presented below by sampling area: Full Tidal Basin, Muted Tidal Basins, and Muted Pocket Marsh. 


A total of 39 species of fish were captured in the FTB in 2008 (Table 1-5). The greatest number of fish 

was captured at Station 2 (the southern station closer to the inlet), made up of 33 species and 

dominated by topsmelt (Atherinops affinis) (60% of the total catch). California grunion (Leuresthes 

tenuis) accounted for 12%, unidentified atherinid juveniles (Atherinidae) 9%, arrow/shadow gobies 




8%, and staghorn sculpin (Leptocottus armatus) 3%. The juvenile atherinids were not developed 

enough to definitively identify, but were likely either topsmelt or grunion. These species often occur 

together during larval and juvenile stages (Ehrlich et al. 1978). The remaining species made up less 

than 2% of the total catch each at Station 2. 

At Station 1, 28 species were captured in 2008, with California killifish (Fundulus parvipinis) and 

topsmelt dominating the catch nearly equally (30% and 29% of the total catch, respectively). Slough 

anchovy (Anchoa delicatissima) made up 14% of the catch and arrow/shadow gobies made up 5%. All 

other species were captured in low numbers (Table 1-5). 

Five species of elasmobranchs were captured in 2008, primarily in April and July and nearly entirely at 

Station 1. Anchovies were captured primarily at Station 1 and only in April and July, with small 

numbers of deepbody anchovy (Anchoa compressa) and northern anchovy (Engraulis mordax) 

captured in the purse seine, and slightly larger numbers of slough anchovy, nearly all of which were 

captured near to shore in a single replicate of the large beach seine in July. Pacific herring (Clupea 

pallasii) and Pacific sardine (Sardinops sagax caeruleus) were captured only in July and in very low 

numbers. Topsmelt and California grunion were present year round at both stations, primarily as 

juveniles. Ten large jacksmelt (Atherinopsis californiensis) were captured, with no juveniles detected. 

All three Paralabrax bass were captured, with the highest numbers in July and October. All were 

juveniles. 

Gobies were common at both stations and were most 

abundant in July. The density of gobies is believed to be 

underrepresented because large numbers were often 

observed swimming out of the seine bag as it was pulled 

up onto shore. Their slippery texture, active nature, and 

narrow bodies allow them to align with the net mesh and 

escape more easily than the other species. Both arrow 

and shadow gobies were captured in FTB. California 

halibut (Paralichthys californicus) and diamond turbot 

(Pleuronichthys guttulatus) were captured in all quarters. 

Table 1-5 also notes the capture of two unidentified fish. 

Juvenile California halibut. 

These two juvenile fish of the same species could not be 

identified in the laboratory and are being sent out to a taxonomist at the time of this report preparation. 

The final identification will be included in the next monitoring report. 




Table 1-5. Summary of fish abundance (# of individuals) in the Full Tidal Basin in 2008. 

Grand 

Total 

Station 1 

January 2008 April 2008 

July 2008 

October 2008 

2008 Station 1 (North) Station 2 (South) Station 1 (North) Station 2 (South) Station 1 (North) Station 2 (South) Station 1 (North) Station 2 (South) 

Grand 

Total 

Station 2 

Beach Otter Purse Beach Otter Purse Beach Otter Purse Beach Otter Purse Beach Otter Purse Beach Otter Purse Beach Otter Purse Beach Otter Purse 

Species 

Seine Trawl Seine Seine Trawl Seine Seine Trawl Seine Seine Trawl Seine Seine Trawl Seine Seine Trawl Seine Seine Trawl Seine Seine Trawl Seine 

Gray Smoothound 7 0 1 5 1 

Thornback 1 0 1 

Bat Ray 9 1 1 1 1 7 

Round Stingray 29 1 6 1 1 13 5 2 2 

California Butterfly Ray 3 0 2 1 

Bonefish 4 0 4 

Pacific Herring 0 1 1 

Pacific Sardine 0 2 2 

Northern Anchovy 16 3 1 15 3 

Deepbody Anchovy 58 16 4 3 51 16 

Slough Anchovy 478 8 27 434 17 8 

California Lizardfish 1 5 1 3 2 

California Needlefish 1 0 1 

California Killifish 1,039 81 1 25 3 4 43 45 992 7 

California Grunion 221 545 2 15 73 138 5 88 7 436 1 1 

Topsmelt 1,015 2,583 2 29 23 51 437 275 57 173 30 243 1,119 293 332 534 

Atherinid, unidentified juvenile 210 373 58 152 35 338 

Jacksmelt 1 9 1 9 

Bay Pipefish 1 40 1 5 3 2 2 12 2 3 11 

Barred Pipefish 0 1 1 

Sebastes , unidentified juvenile 0 1 1 

Staghorn Sculpin 45 135 31 82 13 42 1 11 

Kelp Bass 7 30 3 3 1 1 1 1 26 1 

Spotted Sand Bass 0 7 3 1 1 1 1 

Barred Sand Bass 25 6 13 5 7 1 4 1 

Salema 0 7 7 

Queenfish 2 10 1 1 8 1 1 

Yellowfin Croaker 16 0 16 

Black Croaker 2 8 2 7 1 

Walleye Surfperch 0 1 1 

Shiner Surfperch 0 54 24 2 23 5 

Bay Blenny 1 2 1 2 

Giant Kelpfish 0 7 3 4 

Cheekspot Goby 18 3 2 1 2 2 14 

Arrow/Shadow Goby complex 189 342 4 11 17 1 167 330 1 

Gobiidae, unidentified juvenile 4 1 1 1 3 

California Halibut 9 11 1 6 1 1 1 3 1 1 4 1 

Diamond Turbot 32 21 9 2 6 1 7 2 3 3 4 7 1 6 1 1 

Speckled Sanddab 0 1 1 

Unidentified Fish 0 2 2 

Total Abundance (individuals) 3,444 4,318 111 2 181 183 2 361 175 17 613 341 11 149 875 19 159 690 13 1,623 1,286 4 2 342 64 539 

Area Sampled (m 2 ) 10,617 11,141 729 800 1,040 991 800 1,040 884 800 1,040 969 800 1,040 822 800 1,040 853 800 1,040 822 800 1,040 968 800 1,040 




Less common fish captured over the year included bonefish (Albula vulpes), California lizardfish 

(Synodus lucioceps), and an unidentified juvenile rockfish (Sebastes sp.). All were captured in low 

numbers. Only one California needlefish (Strongylura exilis) was captured (in April 2008), though a 

school of them was observed from the boat at Station 1 in October but not captured. No striped mullet 

(Mugil cephalus) were captured in the basin but were regularly observed, particularly in October, in 

schools in the shallows along the riprap of the basin. 

Ca. butterfly ray in the beach seine. 

The total mass (g) of fish captured in 2008 is presented in Table 1-6. A 

total of 55 kg of fish was captured at Station 1, 68% of which was made 

up of elasmobranchs, primarily bat ray (Myliobatis californica), round 

stingray (Urobatis halleri), gray smoothhound (Mustelus californicus), 

and California butterfly ray (Gymnura marmorata). Topsmelt, 

yellowfin croaker (Umbrina roncador), and California halibut were also 

major contributors to overall mass at Station 1. A smaller total mass of 

19 kg of fish was captured at Station 2, dominated by topsmelt (45%), 

jacksmelt (17%), and diamond turbot (12%). 

It is important to note when reviewing these tables that survey intensity varied slightly between 

stations due to variations in large beach seine haul sizes, so direct comparisons between stations and 

quarters should be made carefully. In addition, the sampling biases between gear types make lumping 

of the catch of all gears together inappropriate. To standardize for the area sampled and to allow direct 

comparisons in density and biomass between stations, Figure 1-8 presents the mean density 

(individuals/m 2 ) by gear by quarter for each station. The results of the first sampling in October 2007 

are included as well. 




Table 1-6. Summary of fish mass (g) in the Full Tidal Basin in 2008. 

Grand 

Total 

Station 1 

Grand 

Total 

Station 2 

January 2008 

2008 Station 1 (North) Station 2 (South) 

April 2008 

Station 1 (North) Station 2 (South) 





Beach Otter Purse Beach Otter Purse Beach Otter Purse Beach Otter Purse Beach Otter Purse Beach Otter Purse Beach Otter Purse Beach Otter Purse 

Species 

Seine Trawl Seine Seine Trawl Seine Seine Trawl Seine Seine Trawl Seine Seine Trawl Seine Seine Trawl Seine Seine Trawl Seine Seine Trawl Seine 

Gray Smoothound 6,605.0 0.0 3,000.0 3,387.0 218.0 

Thornback 895.0 0.0 895.0 

Bat Ray 13,716.0 248.0 248.0 250.0 1,350.0 ###### 

Round Stingray 8,902.0 566.0 1,128.0 159.0 566.0 4,675.0 1,315.0 922.0 703.0 

California Butterfly Ray 7,556.0 0.0 6,800.0 756.0 

Bonefish 308.0 0.0 308.0 

Pacific Herring 0.0 6.1 6.1 

Pacific Sardine 0.0 3.0 3.0 

Northern Anchovy 21.2 2.5 10.0 11.2 2.5 

Deepbody Anchovy 1,072.0 212.4 25.0 59.0 988.0 212.4 

Slough Anchovy 353.6 51.2 130.0 151.2 72.4 51.2 

California Lizardfish 8.0 29.0 8.0 20.0 9.0 

California Needlefish 55.0 0.0 55.0 

California Killifish 2,014.6 76.5 0.1 43.7 15.7 17.7 15.2 10.7 1,983.6 4.4 

California Grunion 692.1 471.7 0.5 1.5 18.1 664.0 6.0 165.3 9.1 296.4 0.4 2.5 

Topsmelt 4,495.7 8,573.7 0.2 718.9 50.2 358.9 2,325.0 2,542.2 458.0 126.2 29.0 1,050.6 1,990.5 937.5 918.4 1,563.8 

Atherinid, unidentified juvenile 16.5 32.6 4.9 11.6 3.5 29.1 

Jacksmelt 340.0 3,169.0 340.0 3,169.0 

Bay Pipefish 0.7 86.8 0.7 3.3 2.4 5.0 5.0 25.6 2.6 11.2 31.7 

Barred Pipefish 0.0 0.7 0.7 

Sebastes , unidentified juvenile 0.0 1.4 1.4 

Staghorn Sculpin 27.3 188.4 5.0 49.1 9.3 47.9 13.0 91.4 

Kelp Bass 54.7 154.3 9.7 40.0 5.0 0.8 13.0 31.0 106.7 2.8 

Spotted Sand Bass 0.0 209.7 39.7 31.0 22.0 66.0 51.0 

Barred Sand Bass 817.0 302.0 315.0 214.0 288.0 41.0 180.0 81.0 

Salema 0.0 6.3 6.3 

Queenfish 10.4 82.0 4.0 9.3 4.0 74.0 1.1 

Yellowfin Croaker 3,078.0 0.0 3,078.0 

Black Croaker 0.5 7.1 0.5 2.7 4.4 

Walleye Surfperch 0.0 2.2 2.2 

Shiner Surfperch 0.0 237.5 73.3 10.4 85.6 68.2 

Bay Blenny 1.5 1.8 1.5 1.8 

Giant Kelpfish 0.0 82.9 15.5 67.4 

Cheekspot Goby 4.5 0.8 0.5 0.3 0.3 0.5 3.7 

Arrow/Shadow Goby complex 46.9 66.5 0.4 1.3 7.9 0.3 38.3 64.9 0.3 

Gobiidae, unidentified juvenile 0.4 0.1 0.1 0.1 0.3 

California Halibut 2,431.0 1,909.0 23.0 1,949.0 1,095.0 94.0 209.0 285.0 19.0 179.0 232.0 255.0 

Diamond Turbot 1,911.7 2,271.4 12.5 422.0 238.9 140.0 13.1 309.0 146.5 260.0 61.1 715.0 17.0 1,347.0 379.0 122.0 

Speckled Sanddab 0.0 10.0 10.0 

Unidentified Fish 0.0 0.3 0.3 

Total Mass (g) 55,435 19,063 25 422 731 365 388 79 3,685 3,426 5,071 2,774 1,956 637 15,739 3,209 18,944 1,409 1,704 5,975 2,921 1,261 2 934 885 1,956 

Area Sampled (m 2 ) 10,617 11,141 729 800 1,040 991 800 1,040 884 800 1,040 969 800 1,040 822 800 1,040 853 800 1,040 822 800 1,040 968 800 1,040 




2.500 

Large Beach Seine 

Fish density (indiv/m 2 ) 

2.000 

1.500 

1.000 

0.500 

0.000 

Oct 07 Jan 08 Apr 08 Jul 08 Oct 08 


0.030 

0.025 

0.020 

0.015 

0.010 

0.005 

Station 1 (North) 

Station 2 (South) 

Otter Trawl 

0.000 


2.000 

Purse Seine 


1.600 

1.200 

0.800 

0.400 

0.000 


Figure 1-8. Mean fish density (individuals/m 2 ) by quarter for large beach seine, otter trawl, and purse seine at 

Stations 1 and 2 in the Full Tidal Basin (note variable y-axis scales between charts) 

The large beach seine chart reflects nearshore fish densities. Trends in the beach seine density over 

time reflect primarily the variations in topsmelt and goby abundance, although the peak in Station 1 

density in October 2008 was due to the capture of large numbers of California killifish. Demersal and 

eelgrass-associated fish density as assessed by the otter trawl was similar at both stations except in the 

October months, when species such as kelp bass (P. clathratus), salema (Xenistius californiensis), 




shiner surfperch (Cymatogaster aggregata), and giant kelpfish (Heterostichus rostratus) were captured 

at Station 2 (Table 1-5). Trends in the purse seine data were driven primarily by the number of 

atherinids captured (which made up 81% of the total purse seine catch in 2008), and reflect the high 

numbers of topsmelt captured in July at Station 2. 

Figure 1-9 presents the mean biomass (g/m 2 ) of fish by gear by quarter for each station. The biomass 

values in the large beach seine chart reflect the regular capture of topsmelt and diamond turbot, 

however the large peak in July at Station 1 is the result of the capture of multiple gray smoothhound, 

round stingray, and California butterfly ray. Fish biomass in the otter trawl was highest in April and 

July when larger and more abundant California halibut, diamond turbot, round stingray, and California 

butterfly ray were captured. Biomass in the purse seine was highest in July with the capture of seven 

bat rays and a school of yellowfin croaker at Station 1, and highest in July at Station 2 with the capture 

of nine jacksmelt and the highest catch of topsmelt for all gear types for the whole year. 

The water quality conditions at the time of each sampling are presented in Table 1-7. All parameters 

measured in the FTB indicated a well-flushed system, with near-oceanic salinities, and warmer 

temperatures at Station 1 than 2, except in January, when Station 1 was slightly cooler. Dissolved 

oxygen was always greater than 5.5 and as high as 9.2 mg/L in the basin. 




20.0 

Large Beach Seine 

Fish biomass (g/m 2 ) 

16.0 

12.0 

8.0 

4.0 

0.0 



1.6 

1.4 

1.2 

1.0 

0.8 

0.6 

0.4 



Otter Trawl 

0.2 

0.0 


20.0 

Purse Seine 


16.0 

12.0 

8.0 

4.0 

0.0 


Figure 1-9. Mean fish biomass (g/m 2 ) by quarter for large beach seine, otter trawl, and purse seine at Stations 

1 and 2 in the Full Tidal Basin (note variable y-axis scales between charts) 




Table 1-7. Water quality measurements taken during quarterly fish sampling in 2008. 


Station Monitoring 

Quarter 

Date 

Sampling 

Event 

Strata Time Depth 

(m) 

Merkel & Associates, Inc. 48 

Temp 

(°C) 

Dissolved 

Oxygen 

Salinity 

(ppt) 

Turbidity 

(NTU) 

1 Jan-08 1/17/2008 BS Midwater 11:00 0.6 11.7 8.60 33.7 8.1 

Jan-08 1/24/2008 PS/OT Surface 11:55 0.3 12.5 8.20 33.5 6.4 

Jan-08 1/24/2008 PS/OT Bottom 11:57 1.5 12.4 8.20 33.5 6.7 

2 Jan-08 1/17/2008 BS Midwater 12:33 0.6 12.9 9.20 33.9 15.0 

Jan-08 1/24/2008 PS/OT Midwater 12:10 0.5 12.9 8.40 33.6 7.2 

MPM Jan-08 1/17/2008 BS Midwater 8:00 0.6 7.9 7.50 30.9 45.0 



Quarter 

Date 

Sampling 

Event 


(m) 

Temp 

(°C) 

Dissolved 

Oxygen 

(mg/L) 

Salinity 

(ppt) 

Turbidity 

(NTU) 

1 Apr-08 4/2/2008 BS Midwater 13:01 0.1 18.6 7.70 35.4 18.0 

Apr-08 4/7/2008 PS/OT Surface 11:55 2.0 19.0 5.99 36.0 10.9 

Apr-08 4/7/2008 PS/OT Bottom 11:52 3.5 19.0 5.80 36.1 13.4 

2 Apr-08 4/2/2008 BS Midwater 14:20 0.1 16.8 8.50 35.0 18.7 

Apr-08 4/7/2008 PS/OT Surface 11:45 2.1 15.7 7.76 35.0 6.8 

Apr-08 4/7/2008 PS/OT Bottom 11:43 3.8 15.3 7.90 35.1 6.7 

MPM Apr-08 4/2/2008 BS Midwater 9:42 0.3 15.9 5.70 34.8 8.0 

WMTB 1 Apr-08 4/7/2008 BS Midwater 14:15 0.3 21.1 6.84 36.9 8.8 



Quarter 

Date 

Sampling 

Event 


(m) 

Temp 

(°C) 

Dissolved 

Oxygen 

(mg/L) 

Salinity 

(ppt) 

Turbidity 

(NTU) 

1 Jul-08 7/7/2008 BS Midwater 9:41 1.3 23.6 5.60 34.8 22.0 

Jul-08 PS/OT Bottom NC NC NC NC NC NC 

2 Jul-08 7/7/2008 BS Midwater 10:23 1.8 20.4 5.80 33.8 4.0 

Jul-08 PS/OT Bottom NC NC NC NC NC NC 

MPM Jul-08 7/7/2008 BS Midwater 15:50 0.3 30.9 10.90 36.5 0.0 

WMTB 1 Jul-08 7/7/2008 BS Midwater 16:25 0.3 26.1 7.30 35.2 2.0 

CMTB 1 Jul-08 7/7/2008 BS Midwater 16:40 0.5 25.1 4.20 54.4 50.0 



Quarter 

Date Sampling 

Event 


(m) 

Temp 

(°C) 

Dissolved 

Oxygen 

Salinity 

(ppt) 

Turbidity 

(NTU) 

1 Oct-08 10/25/2008 BS Midwater 13:17 0.1 21.1 8.20 34.3 5.0 

Oct-08 10/15/2008 PS/OT Surface 11:45 0.2 16.4 8.03 33.9 13.1 

Oct-08 10/15/2008 PS/OT Bottom 11:50 2.0 16.5 8.23 34.2 6.0 

2 Oct-08 10/25/2008 BS Midwater 14:48 0.1 20.0 8.20 33.9 5.0 

Oct-08 10/15/2008 PS/OT Surface 12:35 0.2 15.7 8.53 33.6 10.2 

Oct-08 10/15/2008 PS/OT Bottom 12:40 2.0 15.2 8.55 33.5 7.5 

MPM Oct-08 10/25/2008 BS Midwater 10:30 0.5 19.2 5.20 34.4 16.0 

WMTB 1 Oct-08 11/24/2008 BS Surface * 0.1 37 



CMTB 1 Oct-08 11/24/2008 BS Surface * 0.1 75 



MPM = Muted Pocket Marsh 

WMTB or CMTB = West or Central Muted Tidal Basin 

BS = Beach seine 

PS/OT = Purse seine/Otter trawl 

NC = Not collected 

*Water quality instrument failed in field. Water samples collected for subsequent salinity measurement with a refractometer in the laboratory.




The Muted Tidal Basins were sampled with the small beach 

seine as described in the methods section above, with 

variations in effort each quarter based on conditions within 

each basin. The area and water depth sampled was highly 

variable between quarters due to fluctuating water levels. In 

some cases, unvegetated shoreline was not exposed to pull the 

net up onto at the sampling site, so the net had to be lifted up 

prior to shoreline vegetation, which reduced sampling of fish 

right along the shoreline. Hauls were often filled with dead 

plant debris from decaying pickleweed that was permanently 

inundated by the introduction of tidal waters or heavy rainfall. 

Beach seining the central MTB. 

Six fish species were captured in the west MTB and seven in the central MTB (Table 1-8). Both arrow 

and shadow gobies were captured in the west MTB. Topsmelt and juvenile atherinids were the most 

common species in both basins. California killifish were abundant in October, and various gobies 

were captured in all quarters. Both bay and barred pipefish were observed. Only one other barred 

pipefish was captured in 2008 at Bolsa Chica (at Station 2 in the FTB). A small juvenile striped mullet 

was captured in the far east end of the west muted tidal basin. In 2008 the central MTB was not 

directly open to the FTB for any length of time, just periodically for a few minutes or up to one day. 

Table 1-8. Summary of fish abundance (# of individuals) in the Muted Tidal Basins in 2008. 


July 2008 October 2008 

Species West MTB Central MTB West MTB Central MTB West MTB 

California Killifish 14 68 

Topsmelt 2 76 26 168 301 

Atherinid, unidentified juvenile 120 

Bay Pipefish 1 

Barred Pipefish 1 

Staghorn Sculpin 3 

Striped Mullet 1 

Lonjaw Mudsucker 1 2 5 

Cheekspot Goby 12 3 

Arrow/Shadow Goby complex 8 1 

Total Abundance (individuals) 145 77 30 185 376 

Area Sampled (m 2 ) 126 155 310 170 129 

The water quality conditions at the time of each sampling were presented in Table 1-7. Salinity in the 

west MTB was similar to or just slightly higher than the FTB in each quarter, while salinity in the 

central MTB was considerable higher, measuring 54.4 ppt in July and from 78-78 ppt in October. Both 

MTBs were notably warmer than the FTB in July and October, due to their shallow depth and more 

limited circulation (particularly in the central MTB). Dissolved oxygen was lowest in the central MTB 

in July (4.2 mg/L). 

The mass of the fish captured is presented in Table 1-9. These data show that although gobies made up 

only 4% of the total count, they represented over 16% of the total biomass, due primarily to the large 

size of the longjaw mudsuckers (Gillichthys mirabilis) captured. 




Table 1-9. Summary of fish mass (g) in the Muted Tidal Basins in 2008. 


July 2008 October 2008 

Species West MTB Central MTB West MTB Central MTB West MTB 

California Killifish 33.5 14.7 

Topsmelt 8.0 70.2 12.8 207.7 342.3 

Atherinid, unidentified juvenile 12.0 

Bay Pipefish 2.4 

Barred Pipefish 0.1 

Staghorn Sculpin 10.7 

Striped Mullet 0.3 

Lonjaw Mudsucker 4.8 13.1 117.8 

Cheekspot Goby 2.8 1.1 

Arrow/Shadow Goby complex 2.9 0.4 

Total Mass (g) 36.4 75.0 28.7 242.3 475.2 

Area Sampled (m 2 ) 126 155 310 170 129 


The Muted Pocket Marsh was sampled with the large beach 

seine and was generally found to be low in diversity but high in 

abundance of species foraged on by many birds. A total of nine 

species were captured over the year (Table 1-10). Topsmelt and 

California killifish were the most abundant year round, reaching 

their peaks in July. Staghorn sculpin and longjaw mudsucker 

were occasionally abundant. Diamond turbot was the only 

flatfish captured. Both arrow and shadow gobies were captured. 

Four non-native yellowfin gobies were captured in April. 

Beach seining the Muted Pocket Marsh. 

Table 1-10. Summary of fish abundance (# of individuals) in the Muted Pocket Marsh in 2008. 

Species January 2008 April 2008 July 2008 October 2008 

California Killifish 6 47 879 88 

Topsmelt 190 82 591 293 

Staghorn Sculpin 1 18 

Yellowfin Goby 4 

Longjaw Mudsucker 1 58 

Cheekspot Goby 10 

Arrow/Shadow Goby complex 18 11 1 

Diamond Turbot 3 5 

Total Abundance (individuals) 200 185 1,539 382 

Area Sampled (m 2 ) 1,301 1,206 938 1,301 

The mass of fish captured in the Muted Pocket Marsh is presented by species in Table 1-11. Topsmelt 

accounted for 84% of the total mass during the year. Although abundance of all fish was greatest in 

July, the total mass was highest in October with the capture of larger, more mature topsmelt. The 

diamond turbot captured in January were very small juveniles (20-27 mm standard length), while the 

five captured in April were larger juveniles, ranging in standard lengths from 34-75mm. 




Table 1-11. Summary of fish mass (g) in the Muted Pocket Marsh in 2008. 

Species January 2008 April 2008 July 2008 October 2008 

California Killifish 0.9 28.2 364.5 57.4 

Topsmelt 235.1 231.9 1,213.3 2,205.3 

Staghorn Sculpin 0.1 46.6 

Yellowfin Goby 1.6 

Longjaw Mudsucker 46.0 169.2 

Cheekspot Goby 3.3 

Arrow/Shadow Goby complex 4.4 10.2 1.2 

Diamond Turbot 1.3 26.8 

Total Mass (g) 237.4 388.8 1,757.2 2,263.9 

Area Sampled (m 2 ) 1,301 1,206 938 1,301 

The water quality conditions at the time of each sampling in the Muted Pocket Marsh were presented 

in Table 1-7. In January water temperature was lower than all other sites (7.9°C), then reached a high 

of 30.9°C in July. This basin can experience wide fluctuations in temperature due to its shallow depth 

and restricted circulation from Outer Bolsa Bay through the tide gates. The salinity was fairly stable, 

ranging between 30.9 ppt in January and 36.5 ppt in July. Dissolved oxygen in the MPM ranged from 

5.2 mg/L in October to 10.9 mg/L in July. 

Fish Length 

Of all 42 fish species captured, all but three were represented to some degree by juveniles. The three 

species captured only as mature individuals were thornback (Platyrhinoidis triseriata), California 

needlefish, and jacksmelt. The minimum and maximum standard length of each fish species is 

presented in Table 1-12. 

In Figure 1-10, the number of individuals in each standard length size class is presented by quarter, for 

four species selected based on their numerical dominance, commercial importance, or importance as a 

food source for birds. Only fish captured in the FTB in 2008 (Stations 1 and 2) are included. As 

described in the methods section, standard length was not determined for individuals that were batch 

weighed. Therefore, the size class distributions shown include only individually weighed and 

measured fish (the first 30 individuals of each species in each replicate) and therefore do not always 

reflect the total catch of that species overall. Because the subsampling and batch weigh protocol was 

designed to sample randomly across size classes, it is assumed that these data are generally 

representative of total catch. 

Topsmelt were generally smallest in July, with larger individuals present in April and October. July 

also had the most small slough anchovy, consistent with Emmitt et al. (1991), which reports spawning 

to occur from May to September, peaking in July. These smaller bait fish may have served as a food 

source for nesting terns on the nest sites. Nearly all individuals of kelp bass, a recreational important 

sport fish, were less than one year old based on their length (



Table 1-12. Minimum and maximum standard length (mm) of all fish species captured by quarter at all 

station in 2008. 

January 2008 April 2008 July 2008 October 2008 

Species 

Min. 

SL (mm) 

Max. 

SL (mm) 

Min. 

SL (mm) 

Max. 

SL (mm) 

Min. 

SL (mm) 

Max. 

SL (mm) 

Min. 

SL (mm) 

Max. 

SL (mm) 

Gray Smoothound 860 860 375 635 

Thornback 450 450 

Bat ray (disc length) 170 170 180 250 220 420 

Round Stingray 140 230 135 244 145 210 

California Butterfly Ray (disc length) 215 515 

Bonefish 145 195 

Pacific Herring 49 49 

Pacific Sardine 46 51 

Northern Anchovy 109 109 34 50 

Deepbody Anchovy 78 84 22 128 

Slough Anchovy 49 80 24 82 

California Lizardfish 83 102 

California Needlefish 370 370 

California Killifish 20 62 20 68 14 84 15 59 

California Grunion 25 35 18 124 19 53 36 64 

Topsmelt 22 148 14 138 13 132 32 144 

Atherinid, unidentified juvenile 10 39 10 14 

Jacksmelt 318 318 280 375 

Bay Pipefish 90 175 140 230 48 250 110 244 

Barred Pipefish 111 111 73 73 

Sebastes , unidentified juvenile 35 35 

Staghorn Sculpin 13 62 15 86 58 79 

Kelp Bass 34 83 86 104 19 145 

Spotted Sand Bass 72 105 140 140 

Barred Sand Bass 75 140 115 155 

Salema 26 39 

Queenfish 59 59 24 162 40 40 

Striped Mullet 27 27 

Yellowfin Croaker 105 235 

Black Croaker 17 29 54 54 

Walleye Surfperch 47 47 

Shiner Surfperch 33 64 66 88 

Bay Blenny 36 40 

Giant Kelpfish 69 110 103 145 

Yellowfin Goby 29 33 

Longjaw Mudsucker 145 145 29 115 52 117 

Cheekspot Goby 22 35 13 38 20 35 26 40 

Arrow/Shadow Goby complex 15 31 15 43 14 52 30 38 

Gobiidae, unidentified juvenile 12 13 11 16 

California Halibut 107 107 105 455 100 280 85 245 

Diamond Turbot 12 220 13 175 34 215 160 220 

Speckled Sanddab 78 78 

Unidentified Fish 23 28 


Topsmelt 

January 

April 

July 

October 

Slough Anchovy 

18 

16 

14 

12 

10 

8 

6 

4 

January 

April 

July 

October 

Number of individuals 

2 

20-29 

30-39 

40-49 

50-59 

60-69 

70-79 

80-89 

90-99 

0 

40-49 

50-59 

60-69 

70-79 

80-89 

90-99 

100-109 

110-119 

120-129 

130-139 

140-149 

150-159 

Size Class (mm) 

California Killifish 

70 

60 

50 

40 

30 

20 

10 

January 

April 

July 

October 


10-19 

20-29 

0 

30-39 

40-49 

50-59 

60-69 

70-79 

100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 


Kelp Bass 

January 

April 

July 

October 

50-59 

60-69 

70-79 

80-89 

90-99 

100-109 

110-119 

120-129 

130-139 

140-149 

200-209 

210-219 


Size class distribution of topsmelt, slough anchovy, kelp bass, and California killifish in the Full Tidal Basin in 2008 

Standard length (mm) 


Figure 

1-10 


40-49 

30-39 

30-39 

20-29 

20-29 

10-19 

10-19 

14 

12 

10 

8 

6 

4 

2 

0 



Number of individuals



Discussion 

The 2008 monitoring year included the period of 17 to 25 months post-opening to the ocean. During 

the first survey in October 2007 (13 months post-opening), a total of 17 species were observed in the 

FTB (Merkel & Associates 2008). By October 2008, the cumulative total had increased to 38 species 

after 5 surveys (though only 15 species were captured in the October 2008 survey itself). The only 

species captured in the FTB in 2007 but not 2008 were snubnose pipefish, California tonguefish, and 

striped mullet. The pipefish and tonguefish may still be present but undetected and striped mullet were 

frequently seen, just not captured due to the difficulty of catching them without a gill net. 

The species joining the fish community in the FTB are increasingly associated with structured habitats, 

which is most likely due to the spread of eelgrass habitat, particularly in the southern half of the basin. 

Structure-associated fish such as blennies, surfperch, and kelpfish will likely increase in abundance as 

eelgrass continues to spread in the coming years. The eelgrass also provides nursery habitat for 

species such as topsmelt, which lay eggs on the eelgrass in estuaries and bays (Emmett et al. 1991). 

The creation of the FTB has increased the availability of important bay habitat, provided nursery 

functions for many species of marine fish, and thereby improved southern California fisheries 

resources. Nearly every fish species captured during the 2007 and 2008 monitoring was represented 

by juvenile size classes, demonstrating the linkages between the basin and coastal fisheries, and the 

role of the basin as nursery habitat for spawning or post-larval dispersal. CDFG staff have also 

reported spawning by California grunion on the high sand beach on the north side of the channel 

entrance (K. O’Reilly pers. comm.). The creation of shallow-water habitat rich with primary 

production supplies detritus-based and grazing-based food webs with energy. Ultimately, this energy 

is transferred to fish and used to support increased biomass and numbers. Additionally, this increased 

production is transferred offshore with individuals that leave the basin, or it supports other ecological 

communities through consumption by avian and mammalian consumers. 

The fish community of the MTBs was in its early stages in 2008, with only the western basin open to 

tidal influence and manual adjustments still being made to its tidal range throughout the year. The 

presence of high numbers of topsmelt and California killifish are reflected in the usage of these basins 

by terns and wading marsh birds for foraging. The large numbers of post-larval atherinids captured in 

July suggests the basin is being used for spawning. 

Although the west MTB showed relatively stable water quality, the central and east will continue to 

experience fluctuations in temperature, salinity, and dissolved oxygen that will limit the diversity of 

fish that can persist there. It is anticipated that diversity and distribution of fish will increase once all 

three basins are opened directly to the FTB through their tide gates, allowing for more stable water 

quality, regular tidal flushing, and exchange of fish between the basins. 

The Muted Pocket Marsh continued to provide an abundant food source of small fish for the many 

piscivorous birds that use the marsh. It is key to note that the MPM is not hydrologically connected to 

the FTB of Bolsa Chica, rather it receives muted tidal influence through a water control structure from 

outer Bolsa Bay, through Huntington Harbour, which ultimately opens to the ocean over 6.5 km (4 

miles) to the northwest. It is anticipated that future sampling events may reveal a few more species 

tolerant of lower salinities and limited tidal flushing, however the muted tidal conditions, the water 

control structure, and the distance from the ocean will likely limit the diversity and size of fish that 

ultimately make up the community of the marsh. 





No changes to the fisheries monitoring program are recommended at this time. The next monitoring is 

scheduled to occur in Year 5, with sampling events in October 2010, and January, April, and July 

2011. 

1.4. BENTHIC MONITORING 

Introduction 

The Monitoring Plan calls for benthic invertebrate monitoring to be initiated in Year 2 (October 2007 

to September 2008) and to be repeated in Years 5 and 10 following the opening of the FTB to the 

ocean. The Year 2 sampling was conducted in January and July of 2008. The objective of the benthic 

monitoring task in the Monitoring Plan is to characterize the marine invertebrate food resources 

available to birds and fish, as well as provide an index of general habitat quality in the basin. 

Methodology 

Infauna 

Three benthic sampling stations were established in the FTB: one along the north eastern shore, one 

along the western shore, and one in the southern portion of the basin (Figure 1-11). Three replicate 

collection points were established for each station. At each replicate point, a sediment core was 

collected from the + 0.3-m (+1-foot) NAVD elevation and from the -0.6-m (–2-foot) NAVD elevation. 

These elevations will be referred to in feet throughout this section. The elevations were estimated 

based on the water level compared to a known elevation at the east Water Control Structure in January 

2008. During the second sampling in July 2008, the tidal range in the basin had been altered due to 

tidal muting caused by the accumulated flood shoal in the basin inlet, and the point of core collection 

had to be adjusted accordingly to best approximate the true tidal elevation. 

The sediment cores were collected using a 15-cm diameter corer inserted 

to a sediment depth of 15 cm, and rinsed through a 1.0-mm sieve. The 

sediment area sampled by each core was 0.018 m 2 . Core collection 

unavoidably captured the biota occurring on the surface of the sampled 

core, as well as in the water column for the –2-foot NAVD samples. 

Therefore, the collected samples could include epibenthic and open water 

organisms along with the infauna. Although captured fish were removed 

from the samples, all other organisms were retained and worked up along 

Sieving a sediment core. 

with the infauna. Organisms from each sample were placed in 

containers, preserved in a buffered 10% formalin:seawater solution, and transported to the laboratory 

for subsequent analysis. 

After approximately one week, organisms collected from the benthic cores were transferred in the 

laboratory into 70% isopropyl alcohol. All individuals in each replicate sample were identified to the 

lowest practical taxonomic level, counted, and the wet weight measured. Wet weight was determined 

by transferring the sample, including alcohol, onto a paper towel and blotting quickly to remove excess 

liquid from the animals. Organisms were then transferred to a tared weighing dish and weighed to the 


Benthic Sta 1 Rep2 










0 100 200 400 600 800 

Meters 

Benthic sampling stations 


Figure 1-11 




nearest 0.0001 gram using an analytical balance. All samples were returned to the alcohol solution and 

archived for future reference. 

Because the benthic monitoring program was intended to broadly characterize the communities of 

infaunal organisms within the FTB of Bolsa Chica, species level classification was not deemed 

necessary. Rather, data were assembled into logical, higher-order taxonomic groups. 

Epifauna 

The epibenthic invertebrate sampling program made use of both a 

focused quadrat investigation and a more expansive field effort 

undertaken as a part of the fish community surveys. For the quadrat 

survey, a 1-m 2 quadrat was tossed randomly at each of the sampling 

points, and at the two tidal elevations (+1 foot and -2 feet NAVD), 

utilized for the infauna coring (Figure 1-11). All epifaunal organisms 

present on the surface of the substrate within the quadrat boundary 

were identified and counted. Macroalgae present in the quadrat were 

also recorded. 

Epibenthic quadrat sampling. 

Additionally, during the completion of fish studies described above the incidental by-catch of 

epibenthic invertebrates was collected, identified, and counted to further enhance the detection of 

epibenthic organisms and characterize their distribution, composition, and rough abundance within the 

FTB. Because of the incidental nature of these collections, density information was not generated 

from the count data. 

Only representatives of those organisms that could not be positively identified in the field were 

collected for subsequent laboratory taxonomy and voucher collections. These individuals were 

preserved in a 10% formalin:seawater mixture and transported to the laboratory for identification. 

After approximately one week, organisms were transferred into 70% isopropyl alcohol and identified. 

Results 

Infauna 

In January 2008, nine phyla were collected in the infauna cores, with most taxa represented at both 

elevations. Table 1-13 presents the mean density of infauna for the three replicates at each station and 

elevation. Polychaetes were the dominant taxa, accounting for 61% of the total abundance. Tanaids 

and bivalves were the second and third most abundant (21% and 4% of the total, respectively). Total 

density was higher at the –2-foot elevation than at the +1-foot elevation, driven primarily by greater 

numbers of polychaetes, amphipods, and tanaids at the lower elevation. Table 1-14 presents the mean 

biomass (g/m 2 ) of infauna for the three replicates at each station and elevation in January. Infaunal 

biomass in January was dominated by bivalves, gastropods, and polychaetes at all stations. 




Table 1-13. Mean density of infauna (individuals/m 2 ) in January 2008. 

-2-feet NAVD 

+1-foot NAVD 

Phylum Taxa Station 1 Station 2 Station 3 Station 1 Station 2 Station 3 

Annelida Class Polychaeta 1,733 2,806 7,119 659 2,392 829 

Arthropoda Class Ostracoda 19 

Order Amphipoda 697 132 603 75 75 

Order Decapoda 38 38 19 

Order Mysidacea 19 

Order Tanaidacea 1,394 38 2,881 282 716 

Cnidaria Class Anthozoa 19 113 19 38 

Echinodermata Class Holothuroidea 19 490 19 19 

Subclass Ophiuroidea 19 

Foraminifera Phylum Foraminifera 19 

Mollusca Class Bivalvia 113 207 56 565 169 

Class Gastropoda 38 282 19 264 

Nemertea Phylum Nemertea 75 19 38 151 94 

Phoronida Phylum Phoronida 75 19 19 

Platyhelminthes Class Turbellaria 19 19 38 

Total Mean Density all Taxa (individuals/m 2 ) 4,162 4,200 10,734 1,676 3,107 1,733 




Table 1-14. Mean biomass of infauna (g/m 2 ) in January 2008. 

-2-feet NAVD 

+1-foot NAVD 


Annelida Class Polychaeta 6.582 12.766 19.480 1.203 17.616 1.863 

Arthropoda Class Ostracoda 0.024 

Order Amphipoda 1.292 0.102 0.887 0.041 0.077 

Order Decapoda 2.637 10.938 0.017 

Order Mysidacea 0.011 

Order Tanaidacea 0.358 0.004 0.422 0.038 0.113 

Cnidaria Class Anthozoa 0.661 5.808 0.160 0.571 

Echinodermata Class Holothuroidea 0.051 12.810 0.085 0.041 

Subclass Ophiuroidea 0.013 0.000 

Foraminifera Phylum Foraminifera 0.117 

Mollusca Class Bivalvia 54.750 2.145 8.554 10.100 17.599 

Class Gastropoda 1.183 5.508 2.949 88.497 

Nemertea Phylum Nemertea 0.000 0.763 0.011 0.226 4.040 1.770 

Phoronida Phylum Phoronida 0.239 0.260 0.038 

Platyhelminthes Class Turbellaria 0.026 0.030 0.117 

Total Mean Biomass all Taxa (g/m 2 ) 67.787 40.205 32.418 22.706 128.635 3.840 

In July 2008, eight phyla were collected from the infauna cores, with amphipods making up 36% of the 

total individuals captured, and tanaids making up 27% (Table 1-15). Tanaids and amphipods were 

particularly abundant at the +1-foot elevation of Station 3. 

Table 1-15. Mean density of infauna (individuals/m 2 ) in July 2008. 

-2-feet NAVD 

+1-foot NAVD 


Annelida Class Polychaeta 621 1,582 1,488 320 1,789 3,333 

Arthropoda Order Amphipoda 1,205 395 1,563 94 885 7,533 

Order Decapoda 19 38 19 

Order Isopoda 19 

Order Mysidacea 38 

Order Tanaidacea 38 169 791 19 19 8,927 

Echinodermata Class Holothuroidea 19 151 132 

Subclass Ophiuroidea 56 

Mollusca Class Bivalvia 339 282 339 395 339 94 

Class Gastropoda 433 132 358 678 377 640 

Nematoda Phylum Nematoda 38 

Nemertea Phylum Nemertea 38 169 38 38 245 0 

Phoronida Phylum Phoronida 132 94 19 113 56 

Platyhelminthes Class Turbellaria 19 94 

Total Mean Density all Taxa (individuals/m 2 ) 2,900 2,976 4,746 1,130 3,823 20,734 




Table 1-16 presents the mean biomass (g/m 2 ) of infauna for the three replicates at each station and 

elevation in July. Infauna biomass in July was dominated by bivalves, due to the collection of large 

individuals at both elevations. 

Table 1-16. Mean biomass of infauna (g/m 2 ) in July 2008. 

-2-feet NAVD 

+1-foot NAVD 


Annelida Class Polychaeta 4.962 32.567 13.017 0.386 24.305 2.674 

Arthropoda Order Amphipoda 1.079 0.205 0.955 0.196 0.377 5.571 

Order Decapoda 0.895 1.678 0.006 

Order Isopoda 0.006 

Order Mysidacea 0.194 

Order Tanaidacea 0.002 0.036 0.043 0.002 0.002 1.109 

Echinodermata Class Holothuroidea 0.186 0.527 1.951 

Subclass Ophiuroidea 8.633 

Mollusca Class Bivalvia 26.753 7.162 187.476 190.286 0.047 2.217 

Class Gastropoda 0.670 2.085 1.228 12.309 20.976 2.710 

Nematoda Phylum Nematoda 0.188 

Nemertea Phylum Nemertea 0.207 0.375 0.098 0.363 0.367 0.000 

Phoronida Phylum Phoronida 1.220 0.100 0.075 0.079 0.284 

Platyhelminthes Class Turbellaria 0.036 0.104 

Total Mean Biomass all Taxa (g/m 2 ) 44.608 43.056 204.879 205.220 46.352 14.863 

Figure 1-12 presents a summary comparison between the January and July density and biomass of all 

taxa combined, by station and tidal elevation. There was high variability between all parameters with 

no clear seasonal differences or trends between stations or elevations. 




Infauna density (indiv/m 2 ) 

Infauna density (indiv/m 2 ) 

40,000 

30,000 

20,000 

10,000 

0 

40,000 

30,000 

20,000 

10,000 

0 

600 



Infauna density at -2-feet NAVD 

Station 1 Station 2 Station 3 

Infauna density at +1-foot NAVD 




Infauna biomass at -2-feet NAVD 

Infauna biomass (g/m 2 ) 

Infauna biomass (g/m 2 ) 

500 

400 

300 

200 

100 

0 

600 

500 

400 

300 

200 

100 

0 




Infauna biomass at +1-foot NAVD 




Figure 1-12. Mean infauna density (individuals/m 2 ) and biomass (g/m 2 ) in January and July 2008 by station 

and tidal elevation 




Epifauna 

The epifauna documented in the 1-m quadrat assessment in January 2008 

are presented in Table 1-17 (all replicates combined) and included only a 

few bivalves and tunicates at Station 1 and no animals at Stations 2 or 3, 

although several Navanax inermis were observed outside of the quadrat at 

the –2-foot elevation at Station 2. 

In the July 2008 quadrat sampling, considerably more epifaunal 

invertebrates were observed, with Station 2 at the –2-foot elevation having 

the most animals (Table 1-17). At Stations 1 and 3 there were large groups 

of Bulla gouldiana and egg masses present just outside of the quadrats. 

Also noted in July were large numbers of Hemigrapsus oregonensis and 

Pachygrapsus crassipes throughout the riprap surrounding the FTB. 

Bulla gouldiana and egg masses. 

The epifaunal invertebrates captured in the fishing nets in 2008 

are presented in Table 1-18 by station and sampling quarter (all 

replicates combined). Considerably more diversity was recorded 

than was seen in the quadrat assessment due the greater area and 

depth range sampled. Species occasionally seen in high numbers 

were the pink shrimp Pandalus sp., the small kelp humpback 

shrimp (Hippolyte clarki) commonly associated with eelgrass, 

A. ventricosus size classes in the FTB. 

various tunicates, B. gouldiana, and Argopecten ventricosus. The 

scallop A. ventricosus was captured during every quarter in the FTB and in the full range of sizes from 

newly settled to fully-grown. Six non-native species were identified (as indicated in the table by an 

asterisk), including the Japanese mussel (Musculista senhousia), a highly invasive non-native mussel 

present in many California bays and estuaries and detected during the first benthic monitoring in 

October 2007 (Merkel & Associates 2008). 

Though not measured by the benthic monitoring program, the 

development of the invertebrate community on the shoreline was 

dramatic during 2008, with the loose rocks that are scattered over the 

mud shoreline of the FTB becoming heavily encrusted by the nonnative 

Mediterranean mussel (Mytilus galloprovincialis), the limpet 

Crepidula fornicata, native oysters (Ostreola conchaphila), and 

barnacles (Balanus sp.). These rocks were left behind following the 

completion of the FTB construction and have added complexity to 

the large mudflats of the basin. Octopus (Octopus bimaculoides), navanax, and nudibranchs were 

often observed in the pooled water at the base of the FTB riprap and in the shoreline eelgrass beds. 

Encrusting molluscs on the FTB mudflats. 



Table 1-17. Counts of epibenthic invertebrates detected in 1-m 2 quadrats in January and July 2008. 

January 2008 January 2008 



+ 1-foot NAVD Elevation -2-foot NAVD Elevation + 1-foot NAVD Elevation -2-foot NAVD Elevation 

Phylum Taxa Common name Sta 1 Sta 2 Sta 3 Sta 1 Sta 2 Sta 3 Sta 1 Sta 2 Sta 3 Sta 1 Sta 2 Sta 3 

Phylum Arthropoda Balanus sp. Barnacle 1 6 

Phylum Chordata Styela plicata* Leathery Tunicate 2 1 2 1 

Phylum Mollusca Argopecten ventricosus Pacific Calico Scallop 9 1 

Veneridae Venus Clam 1 

Ostreola conchaphila California Oyster 1 5 4 

Mytilus galloprovincialis* Mediterranean Mussel 2 3 11 

Crepidula fornicata American Slipper Limpet 1 50 

Nassarius tegula Covered-lip Nassa 5 

Plants/Algae Enteromorpha sp. present present 

Total 2 0 0 11 0 0 4 5 2 9 73 0 

* non-native species 




Table 1-18. Counts of epibenthic invertebrates captured in fishing gear during 2008 quarterly fish sampling. 





Phylum Taxa Common name Sta 1 Sta 2 MPM Sta 1 Sta 2 MPM WMTB Sta 1 Sta 2 MPM WMTB Sta 1 Sta 2 MPM WMTB 

Phylum Arthropoda Balanus sp. Barnacle 6 5 

Crangon franciscorum California Bay Shrimp 3 1 

Hippolyte clarki Kelp Humpback Shrimp 205 5 

Palaemon macrodactylus* Oriental Shrimp 1 9 

Pandalus sp. Pink Shrimp 2 5 680 5 200 1 

Penaeus californicus Brown Shrimp 2 2 2 1 4 1 

Portunus xantusii Swimming Crab 3 

Pugettia producta Shield-backed Kelp Crab 1 13 

Pyromaia tuberculata American Spider Crab 3 2 7 

Pachygrapsus crassipes Lined Shore Crab 1 3 1 

Lophopanopeus bellus Black-clawed Crab 2 

Hemigrapsus oregonensis Yellow Shore Crab 4 1 2 

Family Paguridae Hermit Crabs 3 

Phylum Chordata Order Ascidiacea Tunicate 20 200 10 119 2 127 46 6 

Styela plicata* Leathery Tunicate 2 26 

Styela clava* Rough Sea Squirt 9 1 6 

Phylum Cnidaria Aurelia sp. Moon Jellyfish 2 

Polyorchis sp. Bell Jelly 2 2 

Phylum Ctenophora Phylum Ctenophora Comb Jelly 1 

Phylum Ectoprocta Phylum Ectoprocta Bryozoan present 

Zoobotryon verticillatum* Bryozoan present present 

Phylum Mollusca Bulla gouldiana Bubble Snail 181 150 5 70 4 55 13 3 43 102 34 10 

Cerithidea californica California Horn Snail 3 2 1 74 7 

Gastropteron pacificum Pacific Stomach Wing 2 

Navanax inermis Navanax 8 15 9 12 28 9 2 

Navanax inermis eggs Navanax present 

Argopecten ventricosus Pacific Calico Scallop 37 2 88 4 21 56 3 3 

Laevicardium substriatum Egg Cockle 1 

Lyonsia californica California Lyonsia 1 

Protothaca sp. Clam 1 1 

Tellina sp. Clam 1 

Chione sp. Clam 1 

Ostreola conchaphila California Oyster 1 9 4 2 5 

Mytilus galloprovincialis* Mediterranean Mussel 2 17 1 1 1 1 

Musculista senhousia* Japanese Mussel 1 5 

Crepidula fornicata American Slipper Limpet 1 69 4 4 23 5 62 

Nassarius tegula Covered-lip Nassa 2 3 5 13 27 

Octopus bimaculoides Two-spot Octopus 1 

Total 260 389 204 215 133 134 1 108 857 214 2 45 123 367 46 

* non-native species 




Discussion 

Considerable variability in the infaunal invertebrate community was recorded by the coring work. 

Patchiness is an established characteristic of benthic invertebrate communities. Most marine 

invertebrates are rapid colonizers, with community composition being driven by sediment 

characteristics and the frequency and spatial scale of disturbances (Thrush et al. 1996, Levin and 

Talley 2002). The variability see in invertebrate abundance and biomass through time and across 

stations in 2008 can be attributed to an uneven distribution of food or other resources, subtle substrate 

differences, or localized environmental impacts within a community. During the sediment core 

collection, considerable variability in sediment type was noted within stations, with some having a 

hard clay component, others with clean sand, and others composed of very soft muds. Additionally, 

the monitoring program was not conducted at a frequency capable of identifying seasonal patterns or 

with enough replication to detect directional trends amidst the high variability within station 

elevations. 

However, the two sampling events during the second year post-restoration did serve to document that 

the creation of the FTB has provided benthic food resources available to birds, fish, and other 

invertebrates. The created basin was quickly colonized by polychaetes, amphipods, tanaids, bivalves, 

and gastropods. Similar trends were seen at Batiquitos Lagoon following the introduction of marine 

influence to the wetland, which was quickly dominated in both density and biomass by molluscs 

(gastropods and bivalves), annelids (primarily polychaetes), and arthropods (primarily crustaceans) 

(M&A 2009). Benthic monitoring conducted during the comparable second year post-restoration at 

Batiquitos Lagoon (1998) found the mean density of all infauna at the –2-foot elevation to be 3,518 

indiv./m 2 in January and 3,020 indiv./m 2 in July, and at the +1-foot elevation to be 2,265 indiv./m 2 in 

January and 2,321 indiv./m 2 in July (Merkel & Associates 2009). The mean densities found at Bolsa 

Chica in 2008 were within the same order of magnitude, with a density at the –2-foot elevation of 

6,365 indiv./m 2 in January and 3,540 indiv./m 2 in July, and at the +1-foot elevation a mean density of 

2,172 indiv./m 2 in January and 8,562 indiv./m 2 in July. This suggests infaunal density is not falling 

short after the second year post-restoration. 

The FTB experienced considerable tidal muting during the first two years post-restoration, with its 

ability to drain at low tides increasingly hampered over time by the accumulation of the anticipated 

sand shoal in the inlet (see Appendix 2-A). This had the effect of increasing the inundation period at a 

given elevation, so that by the end of 2008, the +1-foot elevation was exposed much less frequently at 

low tides. This inundation shift probably had an effect on the invertebrate community that could not 

be detected by the limited sampling program, but likely influenced the distribution of fauna 

elevationally. Following maintenance dredging scheduled for 2009, the tidal range will rapidly be 

restored and subject the infaunal community to a less gradual shift in tidal elevation. The benthic 

community is anticipated to respond quickly, re-establishing at the elevations with the appropriate 

inundation conditions for their environmental tolerances. Although the response of the benthic 

community to tidal muting is not monitored, it should additionally be kept in mind when considering 

the variability between stations and seasons. 

The lack of lower level taxonomic data makes it impossible to compare the relative health of the FTB 

benthic communities with some popular indices (e.g., Index of Biotic Integrity, Benthic Response 

Index) to local reference standards. However, the basic goal of the sampling program was met; 

monitoring allowed documentation of the conversion of the basin to a tidally influenced bay capable of 

supporting a substantial prey base of infauna for marine fish and birds present in the basin. 




It is clear that the quadrat sampling effort to characterize epibenthic communities did not provide a 

good representation of the invertebrates present. Most epibenthic organisms are highly mobile and had 

vacated the mudflat shoreline during the low tides targeted for the survey work. Additionally, the 

limited frequency of sampling did not capture the pulses of invertebrate usage of the basin that were 

observed during other, more frequent, sampling elements of the biological monitoring program. The 

tracking of invertebrates in the fishing gear more comprehensively and frequently documented the 

epibenthic community, though examination of community parameters, such as density, diversity, and 

evenness, cannot be done due to the incidental nature of the sample collection. 

Epibenthic invertebrates present after the opening of the basin to tidal influence were all marine 

species associated with estuarine or bay environments. It is expected that the species list will continue 

to expand over time as additional sampling is conducted. These macroinvertebrates also provide an 

important prey base for fish and birds in the basin. 


No changes to the benthic monitoring program are recommended at this time. The Monitoring Plan 

calls for benthic monitoring to be repeated in Years 5 and 10 following the opening of the FTB to the 

ocean. 

1.5. WATER QUALITY MONITORING 

The Monitoring Plan calls for water quality monitoring to be initiated in Year 2 of the monitoring. 

Monitoring began in October 2007 (reported in the 2007 report). Quarterly monitoring continued 

through July 2008 and documented water quality conditions through the use of untended, deployed 

instruments programmed to collect continuous data. 

Methodology 

Hydrolab Datasonde 5 ® water quality instruments were deployed at two stations within the FTB: 

Station 1 and Station 2 (Figure 1-1). The station coordinates are provided in Appendix 1-B. These 

locations were positioned to correspond to the general location of fisheries and benthic invertebrate 

monitoring. The depths at water quality Stations 1 and 2 are approximately –1.2 m and –1.3 m NAVD, 

respectively. 

The units were calibrated in accordance with manufacturer specifications and programmed to log water 

depth (m), temperature (°C), dissolved oxygen (DO)(mg/L), turbidity (NTU), and salinity (ppt) at 20- 

minute intervals for 30 days. The units were mounted to weighted boards and deployed in the FTB in 

January, April, and July 2008 to document the second, third and fourth quarter conditions during Year 

2. At the time of deployment and retrieval, water quality readings were taken with an independent, 

tended instrument next to the Hydrolab for quality control purposes. 

Following data collection, the retrieved units were placed in calibration solutions and re-checked for 

accuracy. A technician downloaded the units and transferred the data to the project database for 

review and analysis. The data were reviewed to detect and remove spurious data points that may have 

resulted from algal fouling of probes, signal decay from sediment loading or biotic activities, or that 




were out of the range of the capability of the unit. Accepted data were plotted graphically, numerically 

analyzed, and reviewed to generate summary statistics. 

Water quality monitoring during 2008 was severely impacted by repeated instrument failures. The 

instruments were repeatedly repaired and in some cases replaced, but new malfunctions arose during 

each monitoring interval. Despite intensive coordination and follow-up with the manufacturer, it 

appears that the quality of this previously reliable instrument manufacturer is no longer suitable for the 

present monitoring needs and an alternate instrument manufacturer will be used for future monitoring 

work. 

Results 

In January 2008 the instrument at Station 1 only functioned correctly for the first four days of the 30- 

day deployment (January 10-14). The instrument at Station 2 collected data for 30 days (January 10- 

February 10), with all data acceptable except the second half of the salinity data. The data are 

presented in Figure 1-13. During the four-day period beginning January 10, 2008, temperature ranged 

from 12.8 to 14.3°C at Station 1, with a mean of 13.4°C. During the 30-day period beginning January 

10, 2008 at Station 2, temperature ranged from 11.3 to 15.1°C, with a mean of 13.4°C. Salinity was 

similar at both stations, with a mean of 32.2 ppt at Station 1 (January 10-14) and 32.5 ppt (January 10- 

22) at Station 2. The turbidity data showed considerably more noise than would be expected, and it is 

believed that animals or drift algae regularly passing near the optical sensor likely caused the erratic 

data. The retrieved units were noted to have eggs of the opistobranch Navanax inermis around the 

sensors, which may have interfered with the turbidity readings. In general, turbidity ranged between 0 

and 10 at both stations. Quality control readings taken with a separate instrument at time of 

deployment, retrieval, and mid-way through the logging period measured a turbidity between 5 and 8 

NTU at Station 1 and between 7 and 15 NTU at Station 2. Dissolved oxygen at Station 1 ranged from 

6.8 to 8.9 mg/L, with a mean of 7.9 mg/L during the 4-day logging period. Dissolved oxygen at 

Station 2 ranged from 6.5 to 9.5 mg/L, with a mean of 8.0 mg/L. 

In April 2008 the instrument at Station 1 failed completely for the entire logging period. The 

instrument at Station 2 was on loan from Hydrolab Corporation due to the ongoing maintenance on 

other M&A instruments. This instrument only collected data for the first 18 of the 30 days of 

deployment (April 2-20) and only the temperature and DO probes worked properly. The retrieved data 

are presented in Figure 1-14. During the 18-day period beginning April 2, 2008, temperature ranged 

from 12.7 to 20.1°C at Station 2, with a mean of 16.1°C. Dissolved oxygen at Station 2 ranged from 

5.5 to 9.6 mg/L, with a mean of 7.1 mg/L. 

In July 2008 the instrument at Station 1 collected data for the full 30-day monitoring period (July 1- 

30), but only the temperature and first half of the salinity data were acceptable. The instrument at 

Station 2 collected data for the full 30-day monitoring period, with most of the data acceptable. The 

data are presented in Figure 1-15. At Station 1, temperature ranged from 19.2 to 26.2°C, with a mean 

of 24.0°C. At Station 2, temperature was lower and ranged from 17.2 to 23.7°C, with a mean of 

20.8°C. Salinity was higher at Station 1, ranging from 32.3 to 36.1, with a mean of 34.5 ppt (July 1- 

18), than at Station 2, where salinity ranged from 30.8 to 34.9, with a mean of 33.7 ppt (July 1-30). 

Turbidity data from Station 1 were unacceptable, but quality control readings taken with a separate 

instrument at time of deployment, retrieval, and mid-way through the logging period measured a 

turbidity between 13 and 24 NTU at Station 1. Turbidity data collected at Station 2 were acceptable 


16 

Temperature 

34 

Salinity 

15 

33.5 

33 

Temperature (C) 

14 

13 

12 


32.5 

32 

31.5 

11 



31 

30.5 



10 

13:40:00 22:40:00 7:40:00 16:40:00 1:40:00 10:40:00 19:40:00 4:40:00 13:40:00 22:40:00 

1/10/2008 1/12/2008 1/15/2008 1/17/2008 1/20/2008 1/22/2008 1/24/2008 1/27/2008 1/29/2008 1/31/2008 

7:40:00 16:40:00 

2/3/2008 2/5/2008 

1:40:00 10:40:00 


30 

13:40:00 0:20:00 11:00:00 21:40:00 8:20:00 19:00:00 5:40:00 16:20:00 3:00:00 

1/10/2008 1/13/2008 1/15/2008 1/17/2008 1/20/2008 1/22/2008 1/25/2008 1/27/2008 1/30/2008 

13:40:00 

2/1/2008 

0:20:00 11:00:00 21:40:00 

2/4/2008 2/6/2008 2/8/2008 

Turbidity 

Dissolved Oxygen 

300 

10.5 

Turbidity (NTU) 

250 

200 

150 

100 



Dissolved Oxygen (mg/L) 

9.5 

8.5 

7.5 

6.5 

5.5 

4.5 



50 

3.5 

0 

13:40:00 22:40:00 7:40:00 16:40:00 1:40:00 10:40:00 19:40:00 4:40:00 13:40:00 22:40:00 

1/10/2008 1/12/2008 1/15/2008 1/17/2008 1/20/2008 1/22/2008 1/24/2008 1/27/2008 1/29/2008 1/31/2008 

7:40:00 16:40:00 


1:40:00 10:40:00 


2.5 

13:40:00 0:00:00 10:20:00 20:40:00 7:00:00 17:20:00 3:40:00 14:00:00 0:20:00 

1/10/2008 1/13/2008 1/15/2008 1/17/2008 1/20/2008 1/22/2008 1/25/2008 1/27/2008 1/30/2008 

10:40:00 21:00:00 


7:20:00 17:40:00 


Full Tidal Basin water quality data - January 2009 


Figure 

1-13 


22 

Temperature 

20 


18 

16 

14 

12 


10 

13:40:00 


22:40:00 


7:40:00 16:40:00 


1:40:00 10:40:00 19:40:00 


4:40:00 13:40:00 22:40:00 7:40:00 16:40:00 1:40:00 

4/12/2008 4/13/2008 4/14/2008 4/16/2008 4/17/2008 4/19/2008 


10.5 

9.5 


8.5 

7.5 

6.5 

5.5 

4.5 


3.5 

2.5 

13:40:00 


23:00:00 


8:20:00 17:40:00 


3:00:00 12:20:00 21:40:00 


7:00:00 16:20:00 1:40:00 11:00:00 20:20:00 5:40:00 

4/12/2008 4/13/2008 4/15/2008 4/16/2008 4/17/2008 4/19/2008 

Full Tidal Basin water quality data - April 2008 


Figure 

1-14 


28 

Temperature 

38 

Salinity 

26 

37 

24 

36 

22 

35 


20 

18 

16 

14 




34 

33 

32 

31 

30 



12 

29 

10 

0:00:00 7:20:00 14:40:00 22:00:00 5:20:00 12:40:00 20:00:00 3:20:00 10:40:00 18:00:00 1:20:00 8:40:00 16:00:00 23:20:00 

7/1/2008 7/3/2008 7/5/2008 7/7/2008 7/10/2008 7/12/2008 7/14/2008 7/17/2008 7/19/2008 7/21/2008 7/24/2008 7/26/2008 7/28/2008 7/30/2008 

28 

0:00:00 


8:40:00 17:20:00 


2:00:00 10:40:00 


19:20:00 4:00:00 12:40:00 21:20:00 6:00:00 14:40:00 23:20:00 8:00:00 

7/12/2008 7/15/2008 7/17/2008 7/19/2008 7/22/2008 7/24/2008 7/26/2008 7/29/2008 

Turbidity 


300 

10.5 

250 

9.5 

Turbidity (NTU) 

200 

150 

100 

50 



8.5 

7.5 

6.5 

5.5 

4.5 

3.5 


0 

0:00:00 7:40:00 15:20:00 23:00:00 6:40:00 14:20:00 22:00:00 5:40:00 13:20:00 21:00:00 4:40:00 12:20:00 20:00:00 3:40:00 

7/1/2008 7/3/2008 7/5/2008 7/7/2008 7/10/2008 7/12/2008 7/14/2008 7/17/2008 7/19/2008 7/21/2008 7/24/2008 7/26/2008 7/28/2008 7/31/2008 

2.5 

0:00:00 


8:40:00 17:20:00 


2:00:00 10:40:00 


19:20:00 4:00:00 12:40:00 21:20:00 6:00:00 14:40:00 23:20:00 8:00:00 

7/12/2008 7/15/2008 7/17/2008 7/19/2008 7/22/2008 7/24/2008 7/26/2008 7/29/2008 

Full Tidal Basin water quality data - July 2008 


Figure 

1-15 




from July 1-16 and generally ranged between 5 and 20 NTU. Dissolved oxygen data at Station 1 were 

unacceptable, but deployment, mid-deployment, and retrieval readings taken with a separate 

instrument recorded DO levels ranging between 5.6 and 7.6 mg/L. Dissolved oxygen at Station 2 for 

the 30-day period ranged from 4.1 to 9.4 mg/L, with a mean of 7.2 mg/L. 

Additional spot water quality readings taken at the same stations during concurrent fisheries 

monitoring were presented in the fisheries monitoring section of this report. 

Discussion 

The water quality conditions observed in the FTB during the last three quarters of Year 2 monitoring 

show the tidal marine influence that exists in the basin, reflecting the daily and monthly tidal 

fluctuations seen in the open ocean. All parameters were well within acceptable ranges to support the 

developing fish, invertebrate, and vegetation communities, and are indicative of a well-flushed marine 

environment. On-going physical monitoring of the condition of the inlet and the flood shoal is 

important to ensure proper circulation of the basin and maintenance of good water quality. 

The lack of usable paired temperature data at both stations makes comparisons difficult, but reviewing 

the limited data available in conjunction with water quality measurements taken at the time of the 

fisheries monitoring allows for some assessment. In the April and July months, there was a south to 

north gradient of increasing water temperature. During warmer months the slow-circulating waters in 

at the northern end of the basin tended to have higher temperatures because of increased solar heating. 

The better circulated waters of the southern portion of the basin were more influenced by cooler 

oceanic water, maintaining lower temperatures during the warmer months. Very little difference in 

temperature was seen between the two stations during the January sampling. 

Monthly average sea surface temperature data were obtained from the Coastal Data Information 

Program (CDIP) (http://cdip.ucsd.edu/) for the closest station: 092 San Pedro (offshore of LA/LB 

Harbors, 10 kilometers south of Point Fermin). The mean monthly sea surface temperature in January 

2008 was 13.7 °C, while it was an average of 13.4 °C at both Station 1 and 2 in the FTB. In April 

2008 the sea surface was 14.3°C (compared to 16.1°C at Station 2). In July 2008 the sea surface was 

20.2°C (compared to 24.0°C at Station 1 and 20.8°C at Station 2). The FTB appears to closely match 

the ocean temperature in the winter, with higher temperatures than the ocean in the summer months, a 

condition typically seen in other coastal embayments in the region. 

Dissolved oxygen levels measured at Bolsa Chica were within the expected range and reflected the 

strong influence of diurnal tidal flow, with DO levels rising and falling with tides as water masses with 

differing physical and biotic conditions were exchanged. Dissolved oxygen concentrations in water 

are determined by a number of factors including: production through photosynthesis, atmospheric gas 

exchange, oxygen consumption through biochemical oxygen demand and chemical oxygen demand, 

and saturation capacity as dictated by temperature, salinity, and barometric pressure. The condition of 

the FTB inlet remained suitable to provide enough tidal circulation throughout the basin to maintain 

DO levels generally well above 5.5 mg/L, with daily tidal peaks in the 7.5 to 8.5 mg/L range, even 

during the warm July month when unhealthy drops in DO can be observed in poorly circulated 

systems. 

The salinity data available reflected the absence of significant freshwater input into the FTB, with 

salinities similar to typical oceanic salinities. 





No changes to the water quality monitoring program are recommended at this time. The Monitoring 

Plan calls for water quality monitoring to occur again in Year 5. 

1.6. AVIAN MONITORING 

General Avian Monitoring 

Introduction 

The general avian monitoring program for the Bolsa Chica Lowlands Restoration Project was designed 

to employ similar methodologies and survey units as those used in pre-restoration biological survey 

work. The Monitoring Plan calls for avian monitoring to be conducted once per month in monitoring 

Year 2, with no monitoring in Years 1 and 3. Review of other long-term avian monitoring program 

data, such as the Batiquitos Lagoon Restoration Long-Term Monitoring Program and the Port of Los 

Angeles/Port of Long Beach Biological Baseline Study, suggested that such closely spaced monitoring 

events may not provide significantly more useful information on avian site-usage than quarterly or bimonthly 

surveys. 

With review and concurrence by the Bolsa Chica Steering Committee and the California Coastal 

Commission, a revised monitoring schedule was adopted to conduct the surveys every other month, 

over a period of two years (monitoring Years 2 and 3), for the same total of 12 surveys. This approach 

is more likely to detect annual anomalies, capture natural inter-annual variations in avian usage, and 

better document changes in distribution and site use patterns as the restored site matures. 

Merkel & Associates biologists conducted the avian surveys with assistance from a team of birders 

from Chambers Group, Inc. 

Methodology 

Study Area 

The study site at Bolsa Chica was divided into "zones" (differing from "stations" for the fish and 

benthic studies) for the general avian surveys (Figure 1-16). The U.S. Fish and Wildlife Service 

provided the initial zone boundaries and numbering. The term zone is interchangeable with the term 

cell, often used at Bolsa Chica when numbering the marsh units bounded by service roads throughout 

the site. The created Full Tidal Basin (FTB) was divided up into new zones as described below. 

The Seasonal Ponds at the southeastern side of Bolsa Chica are divided into Zones 2 through 13. 

These zones consist mainly of salt panne with small to extensive expanses of pickleweed, primarily 

along the slightly elevated zone boundaries. Portions are seasonally inundated with fresh to brackish 

water that becomes highly saline later as evaporation concentrates the remaining water over the salt 

panne. 

Zones 14 through 40 and Zone 63 (Future Full Tidal Basin) occur between the Seasonal Ponds and the 

Muted Tidal Basin (MTB) and include Freeman Creek. These zones are very similar to the Seasonal 

Ponds and consist mainly of salt panne and pickleweed, although there are some areas that retain water 

year-round. Zone 36 is primarily a freshwater marsh. 


PM 

50 

66 

47 


Future Full Tidal 




49 

48 

46 

68 

69 

45 

Cordgrass Bench 

42 

41 

40 

39 

38 

70 

63 

71 

30 

37 

72 

29 

19 

31 

28 

32 

33 

34 

35 

14 

20 

27 

21 

26 

25 

36 

9 

13 

22 

23 

24 

73 

10 

12 

2 

11 

0 100 200 400 600 800 

Meters 

Avian Zones 


Figure 1-16 




Zones 41 through 50 and Zone 66 (MTBs) occupy the northeastern section of Bolsa Chica. These 

zones generally contain less salt panne, with broad expanses of pickleweed. Zones 49, 50, 66, and a 

portion of 48 were exposed to muted tidal influence in March 2008. The other zones of the MTBs were 

inundated by tidal overflow and rainwater for much of spring and summer, but were not open directly 

to the FTB. The portions of these zones closest to the residential neighborhoods have an increased 

amount of weedy species, particularly Zone 47. 

Zones 68 through 73 are located within the FTB and are subject to full tidal influence. Zone 68 

(Rabbit Island) is located on the western portion of the site between Inner Bolsa Bay and the FTB. 

This zone previously had more habitat diversity than most of the other zones, with salt marsh, alkali 

marsh, and upland plant species. The introduction of tidal influence in August 2006 resulted in the 

inundation of much of Rabbit Island during high spring tides, causing the existing low elevation 

habitats to die off as the area transitioned into mudflats and low to middle marsh habitats. Zone 69 

borders Rabbit Island to the east. Zone 71 is the newly created California least tern (Sternula 

antillarum browni) and western snowy plover (Charadrius alexandrinus nivosus) nesting site: Nest 

Site 1. Zone 71 is a relatively unvegetated, sandy strip that gently slopes towards the FTB. The 

remaining zones include the intertidal mudflat shelf on the eastern shore and open water bounded by 

riprap along the shoreline. 

The Muted Pocket Marsh occurs north of Rabbit Island and is not hydrologically connected to the 

Bolsa Chica Lowlands; rather it experiences a muted tidal influence through a restricted tidal inlet 

leading to Outer Bolsa Bay. This area is shallow intertidal and subtidal with salt marsh at the higher 

elevations. The northern shore of the Muted Pocket Marsh is lined with large eucalyptus trees that 

died when tidal influence was introduced. The dead trees that remain provide abundant roosting and 

perching habitat for multiple bird species that use the marsh. 

Survey Methodology 

Zones 1 through 66 included the MTB, Future Full Tidal Basin (FFTB), and Seasonal Ponds and were 

surveyed on foot by teams of field biologists. The FTB (Zones 68 through 73) was surveyed primarily 

by vehicles, with multiple stops to view and record birds. Much of Zone 68 was surveyed by foot 

along the pedestrian foot trail. Zone 71, which is a breeding colony for terns and shorebirds, and the 

Muted Pocket Marsh were surveyed on foot. 

Birding in the muted tidal basins. 

Surveys began in October 2007 to mark the start of Year 2 of the 

monitoring program and will continue every other month for a 2-year 

period (see Appendix 1-A for survey dates). Surveys were conducted in 

2008 over a two-day period at each survey interval in such a way as to 

minimize the possibility of double-counts between the two days. The FTB 

and Seasonal Ponds were normally surveyed the first day, and the Muted 

Pocket Marsh, FFTB, and MTBs surveyed the second day. The surveys 

were conducted during a tide low enough to expose the mudflat on the 

eastern shore of the FTB, referred to often as the cordgrass bench, generally 

within a predicted oceanic tide range of +0.9 to +0.3m (+3 to +1 ft) NAVD. 

At this tide, the large sand shoals that had formed in the inlet of the FTB 

where large numbers of gulls, cormorants, and pelicans loaf in the 

afternoon were only minimally exposed. 




Each of five teams, which included 2-3 people (1-2 observers and 1 recorder), was responsible for 

surveying an assigned set of zones over each survey day, which extended from approximately 0700 to 

1200. Team size depended upon complexity of the survey area and seasonal abundance of birds. 

Multiple observers allowed teams to minimize double-counts associated with bird movements between 

zones. 

The field biologists used both binoculars and spotting scopes to identify and count species. All teams 

conducted surveys simultaneously. Data collected included species, number of individuals, activities of 

the birds (foraging, flying, resting, or showing evidence of breeding), and habitats in which the birds 

occurred (open water, nesting site, mud flat, salt marsh, disturbed salt marsh, freshwater marsh, willow 

riparian, baccharis scrub, salt panne [dry], inundated salt panne, and non-native vegetation). Weather 

conditions, including air temperature, wind speed, wind direction, cloud cover, precipitation, and tide 

height, were recorded several times during each survey day. 

Due to the large size of the zones being surveyed, particularly in the FTB, identifications were often 

made over great distances. When it was not possible to identify a bird to the species level due to 

distance, overhead flight, or a limited view of the bird, a less specific identification was made such as 

unidentified gull or unidentified swallow. In cases where challenging lighting conditions and long 

distances prevented the distinction between two species that are very similar and require close 

inspection to identify, the less specific name was used if necessary, i.e. greater and lesser scaup or 

long-billed and short-billed dowitchers were identified as unidentified scaup and unidentified 

dowitchers. 

The accuracy of the bird counts was compromised somewhat on Zones 70 and 71 (Nest Site 1) during 

the June and August surveys. This was due to the large number of birds, including western snowy 

plover, elegant tern (Thalasseus elegans), black skimmer (Rynchops niger), California least tern, royal 

tern (Thalasseus maximus), and Caspian tern (Hydroprogne caspia), that were nesting and rearing their 

young on Nest Site 1. To avoid disturbing the nesting birds, the survey of these zones was conducted 

from either end of the nest site and therefore some avian species, particularly in the center of the site, 

were likely missed. 

Avifauna observed during field surveys were recorded on field data sheets along with collection 

location, time, and name of field observer. All field staff carried a field guide to avoid 

misidentification of uncommon species. In order to avoid double counts of birds, individuals that were 

observed on the boundary of a zone or flying from one zone to another were recorded by only one 

team. This was determined by communicating directly with the other team by radio or phone. If 

contact could not be made, the data were recorded and details noted on the data sheets. At the end of 

each survey, field staff reviewed the data sheets and, if necessary, corrections were made on the data 

sheets to avoid over-counting of individual birds. 

In some cases it was not possible to definitively assess whether a double-count had occurred, 

particularly with large flocks of highly transitory shorebirds and with raptors, which ranged over all 

survey zones and were seen on both survey days. In cases where an over-count is suspected, a note has 

been made on the reported table of birds observed. 

All survey data were initially recorded in the field on hard copy data sheets and then transferred in the 

office to digital database files and checked for accuracy. The database was then queried to extract 




summary information used to prepare tables and figures. Data were analyzed to identify spatial and 

temporal trends in total avian abundance, numbers of species, and patterns of habitat usage, activity, 

and seasonal variation. Each bird species observed was assigned to one of 9 ecological guilds 

(Appendix 1-D). 

Attempts were made to locate results of previous avian monitoring programs within Bolsa Chica for 

comparison. Prior western snowy plover reports prepared by the U.S. Fish and Wildlife Service 

(Fancher, 1998; Fancher et al., 1998, 2001, 2002, 2004, 2005a, 2005b, 2006) and the report on 

Belding’s Savannah sparrow populations in California (Zembal et al., 2006) were located and 

reviewed. Data collected during prior general avian surveys of the site were not located. 

The following results report all data collected from January to December 2008, capturing the last three 

quarters of monitoring Year 2 (January to September 2008) and the first quarter of Year 3 (October to 

December 2008) (see Figure 0-2 for monitoring schedule). 

Results 

A summary of the 2008 avian survey results is presented in Table 1-19. Avian abundance was fairly 

consistent for each survey period with the exception of the June survey, when counts were notably 

lower. This was due to the absence of many shorebirds and wintering ducks, and the timing of the 

survey at the end of the spring migration period. Diversity ranged from 82 to 114 species and was 

highest during December and February surveys. A total of 135 species was observed in 2008, for a 

grand total of 145 species observed since the start of the monitoring period (October 2007 to December 

2008). 

Table 1-19. Summary of 2008 survey dates and number of birds and species observed. 

Date 

Number of 

Birds 

Number of 

Species 

February 14 & 15, 2008 8,948 114 

April 10 & 11, 2008 9,779 99 

June 25 & 26, 2008 3,818 82 

August 19 & 20, 2008 9,387 85 

October 1 & 2, 2008 8,793 84 

December 18 & 19, 2008 10,412 106 

Table 1-20 presents the abundance of each species by survey event. Abundance data tables are 

presented in Appendix 1-E showing the number of each species by zone in 2008. Overall, the ten most 

abundant species in 2008 were western sandpiper (Calidris mauri) (26.0% of the total), followed by 

black-bellied plover (Pluvialis squatarola) (7.8%), elegant tern (5.4%), northern shoveler (Anas 

clypeata) (4.6%), dowitcher (Limnodromus sp.) (4.1%), American coot (Fulica americana) 




Table 1-20. Avian abundance by survey (2008). 

Species Feb 08 Apr 08 Jun 08 Aug 08 Oct 08 Dec 08 Total 

Pacific Loon 1 1 

Common Loon 1 1 2 

Horned Grebe 9 1 7 16 33 

Eared Grebe 60 61 14 42 177 

Pied-billed Grebe 15 9 3 3 8 13 51 

Clark's Grebe 1 1 

Western Grebe 1 1 1 4 7 

White Pelican 29 1 2 2 34 

Brown Pelican 18 5 36 95 9 163 

Double-crested Cormorant 64 33 19 25 69 74 284 

Pelagic Cormorant 1 1 

American Bittern 1 1 

Black-crowned Night Heron 7 5 5 11 2 14 44 

Green Heron 3 2 5 

Reddish Egret* 2 2 2 5 11 

Cattle Egret 1 1 2 

Snowy Egret 19 40 61 84 44 23 271 

Great Egret 8 32 34 25 22 11 132 

Great Blue Heron 15 9 9 14 10 12 69 

White-faced Ibis 2 2 

Mute Swan 1 1 

Snow Goose 1 1 

Canada Goose 6 16 4 23 1 50 

Brant 1 1 2 

Wood Duck 1 1 

Mallard 30 98 50 30 57 265 

Gadwall 166 211 184 23 6 91 681 

Green-winged Teal 255 28 22 231 536 

American Wigeon 454 65 9 801 1329 

Northern Pintail 345 6 4 663 1018 

Northern Shoveler 803 674 2 49 190 648 2366 

Blue-winged Teal 10 4 10 48 72 

Cinnamon Teal 32 45 2 41 120 

Redhead 5 22 25 1 32 85 

Greater Scaup 3 3 

Lesser Scaup 20 3 139 162 

Unidentified Scaup 24 14 38 

Unidentified Duck 2 2 

Surf Scoter 239 48 2 36 325 

Bufflehead 142 14 159 315 

Common Merganser 1 1 

Red-breasted Merganser 4 2 11 17 

Hooded Merganser 1 1 

Ruddy Duck 469 491 19 2 16 172 1169 

Turkey Vulture 10 2 6 2 13 33 

Osprey* 5 1 2 1 9 

White-tailed Kite 1 2 3 

Northern Harrier* 9 2 3 3 17 

Unidentified Dowitcher 692 424 39 290 258 411 2114 

Sharp-shinned Hawk 1 1 2 

Cooper's Hawk 2 1 2 1 6 

Red-tailed Hawk* 3 1 4 2 3 7 20 

American Kestrel 2 2 1 1 4 10 




Table 1-20. Avian abundance by survey (2008) cont’d. 


Merlin 1 1 

Peregrine Falcon 4 1 3 2 10 

Virginia Rail 2 1 3 

Sora 1 2 1 4 

American Coot 657 309 7 41 696 1710 

Black-bellied Plover* 891 129 57 704 1213 1001 3995 

Western Snowy Plover 37 49 34 15 4 139 

Semipalmated Plover 245 107 51 237 172 145 957 

Killdeer 174 75 52 98 244 19 662 

American Avocet 158 146 15 25 53 68 465 

Black-necked Stilt 92 317 223 37 74 52 795 

Willet 109 108 81 182 128 118 726 

Greater Yellowlegs 9 6 5 51 10 23 104 

Lesser Yellowlegs 2 1 3 3 2 11 

Unidentified Yellowlegs 5 13 14 15 75 43 165 

Whimbrel 14 74 9 21 6 14 138 

Long-billed Curlew 86 9 7 21 32 9 164 

Marbled Godwit 172 184 35 229 239 209 1068 

Ruddy Turnstone 8 6 2 9 11 9 45 

Red Knot 3 22 8 3 13 49 

Sanderling 17 8 4 96 6 121 252 

Dunlin 99 100 13 61 273 

Unidentified Sandpiper 100 482 2 68 228 691 1571 

Western Sandpiper 630 2723 8 4867 3735 1342 13305 

Least Sandpiper 22 39 46 33 70 210 

Short-billed Dowitcher 3 3 

Wilson's Phalarope 7 41 48 

Wilson's Snipe 1 1 

Red-necked Phalarope 1 1 24 26 

Unidentified Shorebird 200 200 

Heerman's Gull 5 6 11 

Bonaparte's Gull 1 2 3 6 

Ring-billed Gull 106 41 2 101 15 91 356 

California Gull 148 68 10 27 3 383 639 

Western Gull 71 53 40 114 47 162 487 

Glaucous-winged Gull 1 1 2 

Unidentified Gull 41 33 8 8 3 224 317 

Elegant Tern 7 1341 1085 258 95 2786 

Royal Tern 20 36 30 86 

Caspian Tern 1 137 19 24 5 186 

Forster's Tern 80 28 64 46 17 235 

California Least Tern 1 84 2 87 

Black Skimmer 157 674 56 887 

Unidentified Tern 9 3 12 

Rock Dove 3 2 2 1 2 10 

Mourning Dove 105 72 93 97 228 249 844 

Burrowing Owl 1 1 2 

White-throated Swift 3 1 4 

Costa's Hummingbird 1 1 2 

Anna's Hummingbird 18 14 5 16 11 15 79 

Allen's Hummingbird 4 1 4 8 6 1 24 

Unidentified Hummingbird 1 1 

Belted Kingfisher 3 2 2 7 




Table 1-20. Avian abundance by survey (2008) cont’d. 


Northern Flicker 1 1 

Pacific-slope Flycatcher 1 1 

Black Phoebe 9 1 14 19 23 29 95 

Say's Phoebe 6 1 1 17 16 41 

Western Kingbird 1 2 3 

Cassin's Kingbird 2 1 1 3 7 

Loggerhead Shrike 1 1 1 3 

American Crow 33 7 25 8 15 4 92 

Common Raven 6 8 2 16 

Violet-green Swallow 42 8 50 

Tree Swallow 23 23 46 

Cliff Swallow 44 26 222 53 24 369 

Northern Rough-winged Swallow 83 11 10 3 1 3 111 

Barn Swallow 42 18 62 107 2 231 

Unidentified Swallow 30 4 34 

Bushtit 13 9 29 20 71 

House Wren 2 1 6 3 6 18 

Bewick's Wren 5 1 2 8 

Marsh Wren 12 3 4 1 2 6 28 

Blue-gray gnatcatcher 6 1 7 

Northern Mockingbird 3 4 9 16 

European Starling 17 13 10 2 19 10 71 

American Pipit 30 11 41 

Orange-crowned Warbler 3 3 

Yellow-rumped Warbler 27 1 2 51 81 

Common Yellowthroat 12 22 24 17 10 6 91 

California Towhee 1 2 1 6 3 2 15 

Savannah Sparrow 43 22 14 504 236 819 

Belding's Savannah Sparrow 113 257 402 156 135 19 1082 

Song Sparrow 16 18 11 13 7 65 

White-crowned Sparrow 28 24 9 78 139 

Unidentified Sparrow 9 4 13 

Western Meadowlark 48 7 2 1 20 11 89 

Red-winged Blackbird 20 35 2 2 12 71 

Great-tailed Grackle 26 19 45 

Brewer's Blackbird 32 32 

Brown-headed Cowbird 3 3 

House Finch 211 84 257 96 124 158 930 

American Goldfinch 1 7 21 29 

Lesser Goldfinch 6 6 6 7 25 

Unidentified Goldfinch 1 1 

House Sparrow 1 8 9 

Total 8,948 9,779 3,818 9,387 8,793 10,412 51,137 

* Species suspected of overcounting in some cases due to multiple sightings that could not be determined as either unique or duplicate. 




(3.3%), American wigeon (Anas americana) (2.6%), ruddy duck (Oxyura jamaicensis) (2.3%), 

Belding’s Savannah sparrow (2.1 %), and marbled godwit (Limosa fedoa) (2.1%). 

The most abundant bird guild was shorebirds in all survey periods except June (3,567 individuals in 

February, 5,028 individuals in April, 7,059 individuals in August, 6,773 individuals in October, and 

4,407 individuals in December) (Figure 1-17). Shorebirds made up an average of 53.8% of all birds 

observed, with a high of 77% in October 2008. During June the number of shorebirds dropped to 656 

individuals and represented only 17.2% of the birds present. 

Number of birds 

8,000 

7,000 

6,000 

5,000 

4,000 

3,000 

Jan 2008 

Apr 2008 

Jun 2008 

Aug 2008 

Oct 2008 

Dec 2008 

Mean- all 2008 surveys 

2,000 

1,000 

0 

Aerial Fish 

Foragers 

Coots and 

Rails 

Dabbling 

Ducks/ 

Geese 

Diving Ducks/ 

Grebes/ 

Cormorants 

Gulls Herons Raptors Shorebirds Upland 

Birds 

Figure 1-17. Avian abundance by guild at Bolsa Chica during 2008 surveys 

The most numerous shorebird species in 2008 was the western sandpiper with its highest numbers 

during August (4,867 individuals and 51.8% of all species), October (3,735 individuals, 42.4%) and 

April (2,723 individuals, 27.8%). There were low counts in December (1,342 individuals), February 

(630 individuals), and almost no western sandpipers in June (8 individuals). Other abundant 

shorebirds included black-bellied plover, dowitcher, marbled godwit, semipalmated plover 

(Charadrius semipalmatus), black-necked stilt (Himantopus himantopus), killdeer (Charadrius 

vociferous), and willet (Tringa semipalmata) in that order. In June, when most of the shorebirds were 

absent, the black-necked stilt was the most common shorebird. This is one of several shorebirds that 

nest at Bolsa Chica. The snowy plover is the only listed shorebird observed at Bolsa Chica and our 

count of 49 individuals in April was almost identical to the 50 adults observed on a focused count for 

this species in May. 

The second most abundant guild was dabbling ducks/geese which had high counts in December (2,721 

individuals), February (2,125 individuals), and April (1,151 individuals) and remained present year 

round in smaller numbers. The most abundant of the dabbling ducks were northern shoveler, 

American wigeon, and northern pintail (Anas acuta). American wigeon and northern pintail were 

absent during the June and August surveys and present in only very small numbers during the February 




and April surveys. Northern shoveler was present in small numbers only during the surveys in June 

and August. Several brant (Branta bernicla) were recorded foraging in eelgrass in the FTB. 

The third most abundant guild in 2008 was upland birds, primarily due to the inclusion of Savannah 

sparrow (Passerculus sandwichensis) in this guild, including both the Belding’s Savannah sparrow, a 

species that remains in the salt marsh year round, and any other migrating Savannah sparrows. The 

number of individuals in the guild remained fairly stable for the entire year although there was a small 

drop in numbers during April (711 individuals) and August (671 individuals). June had the highest 

count of upland birds with 1,244 individuals and made up 32.6% of all birds observed during that 

survey. Counts during the winter months were comparable to the June count including; 1,162 

individuals (13% of all birds) in October, 1,012 individuals (9% of all birds) in December, and 1,106 

individuals in February. The highest numbers for Savannah sparrow were during the month of October 

when a total of 639 individuals were counted. February and August, which correspond with the 

beginning and end of the Belding’s Savannah sparrow breeding season, were the lowest numbers with 

156 individuals observed. June counts were much higher at 416 individuals. 

Other abundant upland species include house finch (Carpodacus mexicanus), and mourning dove 

(Zenaida macroura). Cliff swallow (Petrochelidon pyrrhonota), northern rough-winged swallow 

(Stelgidopteryx serripennis), barn swallow (Hirundo rustica), violet-green swallow Tachycineta 

thalassina, and tree swallow (Tachycineta bicolor) were all observed at Bolsa Chica although the 

highest counts of each species were observed at different times of the year. Northern-rough winged 

swallow (83 individuals) and violet-green swallow (42 individuals) were most numerous in February. 

Tree swallow was most numerous in both February and December with 23 individuals observed each 

month. Cliff swallow were most numerous in June (222 individuals) and barn swallow most numerous 

in August (107 individuals). The great-tailed grackle (Quiscalus mexicanus), not native to the area but 

an invading species from Sonora or southern Arizona, was observed breeding during April and June 

surveys but was not observed during any other surveys. 

Aerial fish foragers were the fourth most abundant guild and accounted for 8.8% of all birds observed 

over the year. The elegant tern was the most common, accounting for 62.1% of all aerial fish foragers. 

The majority of the remaining species in this category included; in descending order of abundance, 

black skimmer, Forster’s tern (Sterna forsteri), Caspian tern, California least tern, and royal tern. All 

of these species nest at Bolsa Chica in the area of the FTB and had their highest numbers during the 

June survey. These species were most likely undercounted during June and August due to limited 

access to their high-density nesting area in Zone 71 (Nest Site 1). It is important to note that the 

elegant tern count (maximum of 1,330 in April 2008) only reflects their usage of Zone 71, which 

represents only a small portion of the total breeding population at the Bolsa Chica Ecological Reserve. 

The majority of elegant terns nested at North Tern Island in Inner Bolsa Bay, outside the survey focus 

of this monitoring program (see Figure 0-1). An estimated 7,000 elegant tern nested on NTI in 2008 

(Mike Horn, pers. comm.). 

Other aerial fish foragers included belted kingfisher (Megaceryl alcyon), which were seen in low 

numbers, and brown pelican (Pelecanus occidentalis), which were observed loafing and foraging 

nearly year-round (none detected in February) in moderate numbers. 

Diving ducks/grebes/cormorants were the fifth most abundant guild and accounted for 4.9% of all 

birds observed over the year. Ruddy duck was the most common diving duck accounting for 46.6% of 




all individuals in this category, with the majority found during the February and April surveys. Other 

common birds in this guild were surf scoter (Melanitta perspicillata), bufflehead (Bucephala albeola), 

scaup (Aythya sp.), ruddy duck, and eared grebe (Podiceps nigricollis). Double-crested cormorant 

(Phalacrocorax auritus) were also a common species in this category. They were observed year 

round, even nesting on the site, but were observed in higher numbers during the winter months of 

October through February. 

The remaining guilds were represented in the following order of descending abundance: gulls, coots 

and rails, herons, and raptors. Coots and rails were primarily American coot. A notable member of the 

heron guild was the reddish egret (Egretta rufescens), regularly seen in the FTB and Muted Pocket 

Marsh. Raptors are normally lowest in number due to their position in the food chain. They are also 

among the more likely to be over-counted due to their mobility and size of their territories. Attempts 

were made between surveyors to eliminate overcounts; however, this is difficult over time and between 

consecutive survey days. Eleven species of raptor were observed in 2008 including red-tailed hawk 

(Buteo jamaicensis), turkey vulture (Cathartes aura), American kestrel (Falco sparverius), osprey 

(Pandion haliaetus), northern harrier (Circus cyaneus), Cooper’s hawk (Accipiter cooperii), whitetailed 

kite (Elanus leucurus), peregrine falcon (Falco peregrinus), sharp-shinned hawk (Accipiter 

striatus), burrowing owl (Athene cunicularia), and merlin (Falco columbarius). 

Avian Usage of the Survey Area 

Assessing the avian usage of Bolsa Chica is complicated due to the frequent movements of the 

shorebirds and waterfowl between areas such as the Seasonal Ponds and FTB within and between days. 

However a general overview of the use of these areas is provided. 


The 158-ha FTB is the largest, and was the most highly utilized, portion of the site. A total of 25,413 

individuals (49.7% of all birds observed), representing 103 species, were counted in the basin in 2008. 

The heavy usage of this area was strongly linked to the low tidal elevation during which the surveys 

were always conducted. During low tide, shorebirds (which made up 72.1% of all birds) foraged on 

the intertidal mudflats along the eastern shore of the basin (cordgrass bench), southwestern shoreline 

(Nest Site 1), and around Rabbit Island. Gulls utilized the exposed mudflats for loafing during the low 

tides. As the tide rose at the end of the surveys, many of the shorebirds and loafing gulls and pelicans 

would move to the zones east of the FTB berm once the mudflat was flooded in the FTB. This high 

tide usage is not reflected in the present dataset due to intentional low tide timing. 

Nest Site 1 in the FTB was highly utilized by aerial fish foragers, particularly during the April through 

August surveys when the terns and skimmers were nesting. Overall 94% of all aerial fish foragers 

were recorded in the FTB. Current research by California State University Fullerton has been 

examining usage of the FTB by terns, particularly elegant terns, and found foraging activity to be 

rather limited in the FTB, with the birds foraging primarily in the ocean. During the present 2008 

monitoring, a total of only 15 elegant terns were documented foraging in the FTB. Among the other 

terns, there were 15 least tern, 8 Caspian tern, 38 Forster’s tern, four royal tern, and 26 black skimmer 

documented foraging in the FTB. 




Future Full Tidal Basin 

A total of 9,105 individual birds (113 species) were counted in the 104-ha FFTB in 2008. The most 

abundant guilds in the FFTB were upland birds, dabbling ducks, and shorebirds, respectively. The 

most abundant upland bird was Belding’s Savannah sparrow that utilized the pickleweed-dominated 

salt marsh and house finch that utilized the weedy uplands available in this area. These zones are dry 

and highly disturbed in some areas. The ponded water within Zones 38, 63, and 30 was utilized by 

dabbling ducks and shorebirds. American coot is also very abundant in this region. 


The 50-ha Seasonal Ponds were utilized by 8,241 individual birds during the 2008 surveys, 

representing 92 species. These ponds are a very important habitat for waterfowl, shorebirds, and 

Belding’s Savannah sparrow. Zone 11 makes up the largest portion of the Seasonal Ponds, supports 

the most diverse habitats, and is the least disturbed of the Seasonal Ponds zones and as a consequence 

most bird activity was focused on this zone. The degree of inundation by rainfall fluctuates from year 

to year, but generally it provides a mix of shallow water, salt panne, riparian forest, freshwater marsh, 

and salt marsh. 

The most abundant guilds in the Seasonal Ponds were shorebirds and dabbling ducks. Western 

sandpiper was the most abundant shorebird, representing 67.9% of all shorebirds and 30.1% of all 

birds observed in this area. This area was also occupied by species such as the black-bellied plover, 

semipalmated plover, American avocet (Recurvirostra americana), black-necked stilt; the latter two 

nested in the Seasonal Ponds. The most common dabbling ducks were the northern shoveler, gadwall 

(Anas strepera), and American wigeon, indicating the importance of the shallow water in the inundated 

salt panne for foraging and the exposed salt panne for resting. The Seasonal Ponds also support 

considerable expanses of pickleweed that were heavily utilized for nesting by Belding’s Savannah 

sparrow. 

The Seasonal Ponds are much more heavily used by shorebirds during high tide, when the mudflats of 

the FTB are no longer exposed and large flocks of sandpipers, black-bellied plover, and semipalmated 

plover move over the berm into the ponds. This condition is not reflected in this dataset. 


The 77-ha MTB was the least utilized of all the survey areas, with the most abundant guilds being 

shorebirds and upland species. The MTBs had a total of 4,633 individuals (95 species) during the 

2008 surveys. Western sandpiper, black-bellied plover, and killdeer were the most abundant shorebird 

species, and all utilized areas of open mudflat and salt panne primarily at the western ends of the 

MTBs. As with the Seasonal Ponds, the MTBs were much more heavily used by shorebirds at high 

tide, when mudflat was lost in the FTB but remained in the MTBs due to the muting by, or continued 

closure of, the tide gates. 

The most abundant upland species during the surveys were Belding’s Savannah sparrow and house 

finch. The MTBs are an important area for Belding’s Savannah sparrow nesting, providing large 

expanses of pickleweed. In 2008, there was standing water in much of the MTBs due to the opening of 

the west MTB to the FTB and subsequent flow into the central and east MTBs, however Belding’s 

Savannah sparrow usage remained high. 

The ponded water in the MTBs was also utilized by least tern and Forster’s tern for foraging. 





The 14-ha Muted Pocket Marsh is primarily shallow open water and mudflat and therefore highly 

utilized by shorebirds and dabbling ducks. The Muted Pocket Marsh had a total of 3,745 individuals 

(88 species) during the 2008 surveys. Although this area appeared to have the lowest number of 

individuals and species, this is solely due to its size. Compared to the highly utilized FTB, which had 

an overall total of 161 birds per hectare, the Muted Pocket Marsh supported 268 birds per hectare. The 

most abundant of dabbling ducks included American wigeon and green-winged teal (Anas crecca). 

The most abundant shorebirds were dowitcher, which frequented the marsh in high numbers during the 

winter months. 

The rampikes of dead eucalyptus trees that ring the basin were used for perching by osprey, doublecrested 

cormorant, and belted kingfisher. The dead Myoporum along the shorelines were frequently 

occupied by roosting black-crowned night heron (Nycticorax nycticorax). 

Avian Distribution and Abundance by Habitat Type 

Mudflats were the most utilized habitat type during the 2008 surveys (37.5% of all birds observed) 

(Figure 1-18). Large and small shorebirds had the highest utilization of the mudflats for foraging and 

resting. During the June survey, the sand shoals in the FTB were the most utilized habitat due to their 

considerable size at that time and the absence of most shorebirds from the basin. The inundated salt 

panne was also highly utilized (19.0% of all birds), particularly by foraging northern shoveler, 

American coot, ruddy duck, northern pintail, and American widgeon. This is followed by usage of salt 

marsh habitat (13.5% of all birds) and open water habitat (12.3% of all birds). Salt marsh habitat 

usage, unlike the other major usage habitat types, appears to increase during the breeding season and 

continue to increase into the fall surveys. This can largely be attributed to breeding Belding’s 

Savannah Sparrow; however, during the August and October surveys there was also an increase in 

large shorebirds and upland birds (swallows and morning dove). 

25,000 

90 

20,000 


Number of species 

80 

70 


15,000 

10,000 

60 

50 

40 

30 

Number of species 

5,000 

20 

10 

0 

Salt 

Marsh 

Dist urbedFreshwat er Willow/ 

Salt Marsh Marsh Riparian 

Mulefat Decaying/ 

Scrub Transit ional 

Salt 

Panne 

Inundat ed 

Salt Panne 

Nest 

Site 

Open 

Wat er 

Riprap Mudf lat Sand 

Shoal 

Coast al Non-nat ive Urban/ 

Sage ScrubVegetationDist urbed 

0 

Figure 1-18. Avian abundance by habitat type at Bolsa Chica during 2008 surveys 




The extent of these habitats varies greatly (Table 1-3). When standardized by the area of each habitat 

type, bird densities in February were greatest in the freshwater areas such as mulefat scrub (1,478 

birds/ha), freshwater marsh (121 birds/ha), and willow/riparian (81 birds/ha). In April the bird 

densities were highest in mulefat scrub (455 birds/ha), mudflat (134 birds/ha), and decaying 

transitional vegetation (104 birds/ha). June had the highest bird densities on the intertidal sand shoal 

(199 birds/ha). August bird densities were greatest on the mudflat (128 birds/ha), the intertidal sand 

shoal (99 birds/ha), and on the nest site (60 birds/ha). In October the birds densities were highest on 

the mulefat scrub (398 birds/ha), decaying transitional vegetation (78 birds/ha), salt panne and 

inundated salt panne (39 species/ha), and disturbed salt marsh (37 birds/ha). December bird densities 

were greatest in the foraging and resting area such as decaying transitional vegetation (732 birds/ha), 

mudflat (82 birds/ha), and the intertidal sand shoal (67 birds/ha). 

Flying birds were recorded in the habitat over which they were flying at the time of observation, 

though they may not necessarily use that habitat on the ground. Thirteen percent of all birds were 

flyovers. To look at species richness, all birds recorded as flying were disregarded and only birds on 

the ground considered. Species richness was highest in the salt marsh (85 species), open water (74 

species), mudflat (66 species), and inundated salt panne (62 species) (Figure 1-18). All other habitats 

had 50 species or less in 2008. 

As noted in the prior annual report, the heavy usage of the intertidal sand shoals in Zone 73 (inlet) at 

low tide by gulls, cormorants, terns, and pelicans was not fully captured by these surveys, though 

observed regularly in late afternoon low tides at the site. The survey also cannot account for 

movement of birds into and out of the survey area from Bolsa Chica State Beach and from Inner and 

Outer Bolsa Bay. 

Gulls on sand shoal in the Full Tidal Basin. 

Discussion 

The Bolsa Chica Lowlands Restoration Project included several elements that have enhanced the avian 

community within the project area. The creation of the FTB is the most notable, which involved 

removing existing oil wells, excavating a basin, and constructing a permanent opening to the ocean in 

2006. Its new mudflats and open water were the most used area in 2008, providing expansive foraging 

and loafing habitat to 91 species, including seven that were found in no other area of the site: brant, 

common loon (Gavia immer), common merganser (Mergus merganser), glaucous-winged gull (Larus 

glaucescens), pelagic cormorant (Phalacrocorax pelagicus), surf scoter, and western grebe 




(Aechmophorus occidentalis). As reported above, in 2008 the basin supported a diverse marine 

community, including fish, invertebrates, and eelgrass, which provided important food resources for 

migrating, resident, and nesting birds. As eelgrass habitat expands in the basin in the coming years, 

more surf scoter, brant, and other diving birds will likely frequent the basin. 

The FTB design included low intertidal mudflat suitable for the introduction of cordgrass. The 

expansion of the transplanted cordgrass over time should provide habitat attractive to light-footed 

clapper rails in the coming years. To facilitate the development of this habitat, it is critical that 

appropriate tidal ranges and inundation frequency of the mudflat be maintained through regular 

maintenance dredging of the basin inlet. 

The Project also created three nest sites that have substantially increased the available habitat for 

nesting terns and plovers. The usage of these site and resulting reproductive success will be discussed 

further in the next section. 

The third most abundant guild was dabbling ducks/geese, which had high counts in February (2,354 

individuals), April (982 individuals), and June (322 individuals) and in smaller numbers during the 

August survey (31 individuals). The most abundant of the dabbling ducks were northern shoveler, 

gadwall, American wigeon followed closely by green-winged teal, northern pintail, and mallard. Most 

of the dabbling ducks/geese were observed during February and April with species and numbers 

dropping in June and absent in August. Several brant were recorded foraging in eelgrass in the FTB 

and mallard were the only species still present during the August survey. 

Another element of the Project involved the introduction of muted tidal influence to the Muted Pocket 

Marsh. Although avian data from this previously freshwater site have not been located, the usage of 

the basin following the conversion to a saltwater system has been notable. This site had consistently 

high densities of birds, provided an easily accessible viewing area for the public, and supported several 

Belding’s Savannah sparrow breeding territories. 

Prior to the restoration, the expanses of pickleweed in the Muted Tidal Basins were non-tidal and 

experienced hypersaline sediment conditions and the environmental extremes of wet and dry seasons. 

The Project design included restoration of a muted tidal influence to these three basins in order to 

provide greater environmental stability to the salt marsh, improve its quality for Belding’s Savannah 

sparrow, and to create a more functional salt marsh with open water and intertidal mudflats, as well as 

low and mid marsh. Only the west MTB was open to tidal influence in 2008. This basin maintained a 

high level of Belding’s Savannah sparrow nesting while also providing open water for large numbers 

of wintering ducks and foraging terns, and some mudflat for foraging sandpipers. The regulation of 

water levels in this basin was hampered by the accumulation of sand in the FTB inlet, preventing tides 

from falling as low as desired in the FTB and west MTB. It is anticipated that after the 2008/2009 

maintenance dredging cycle, and the opening of the other two MTBs to tidal influence, the entire MTB 

system will be able to move toward an equilibrium of habitat availability for multiple avian guilds. 

Diversity within the entire study area (135 species in 2008) is comparable to diversity observed at 

other coastal salt marshes in southern California. The bird usage of Batiquitos Lagoon in San Diego 

County was monitored, using similar methods to those of the present study, for 10 years following the 

restoration of tidal influence to the system. Two years post-restoration, 133 species were documented 

at Batiquitos Lagoon (M&A 1999). Batiquitos Lagoon is a smaller site (approximately 2/3 the size), 




but includes more diverse habitats in a more balanced distribution. The Huntington Beach Wetlands 

are located roughly five miles to the south of Bolsa Chica and have been monitored for the past 2 years 

in anticipation of the restoration of tidal influence to Brookhurst and Magnolia Marshes, part of the 

overall wetland complex. From January 2007 to January 2009 a total of 115 bird species were 

documented in quarterly saturation surveys of Brookhurst, Magnolia, and Talbert Marshes. These 

marshes contain similar expanses of non-tidal pickleweed marsh. Surveys conducted following 

restoration of tidal influence to Brookhurst Marsh in 2009 and Magnolia Marsh in 2010 will provide 

better comparisons for Bolsa Chica. 


• Continue modified avian monitoring schedule, expanding the monthly Year 5 monitoring called for 

in the Monitoring Plan to instead conduct the surveys every other month, distributed over a period 

of two years (monitoring Years 5 and 6). 

Light-footed Clapper Rail Monitoring 

Surveys for the light-footed clapper rail (Rallus longirostris levipes) will not be initiated until suitable 

cordgrass habitat has developed to an extent and quality to attract clapper rails. The status of the 

cordgrass transplants was detailed in the vegetation section of this report. 

Belding’s Savannah Sparrow Monitoring 

Methodology 

Two complete surveys for the state endangered Belding's Savannah 

sparrow were performed in 2008. The number of surveys was 

increased from one survey in 2007 to two in 2008 in order to improve 

the reliability of the number of territories recorded. The results of both 

2008 surveys will be reported. The first survey was conducted on 

April 21 and 22, 2008 and the second on May 12 and 13, 2008. At this 

time the sparrows were well into their breeding season and therefore 

displaying territorial and breeding behavior. All areas with potentially 

suitable breeding habitat for the Belding's Savannah sparrow 

(pickleweed-dominated salt marsh) were surveyed. The site was 

surveyed on foot by qualified biologists using binoculars and spotting 

scopes. Surveys were performed between 0530 hours and 1100 hours, 

but generally ended by about 0930. Weather conditions including air 

temperature, cloud cover, precipitation, and approximate wind speed 

were recorded regularly throughout the survey. 

Photo: Laura Gorman 

Belding’s Savannah sparrow. 

In 2007 the survey program included a calibration training period with Dick Zembal prior to 

conducting the surveys so that data collected would be consistent between individuals and in 

comparison to past surveys conducted at the site and throughout the state (Zembal et al, 2006). This 

method gives a rapid estimate of the number of territories and their locations. The same team 

conducted the surveys in 2008 to minimize further surveyor bias. Surveys will continue to be 

conducted annually in the future to document changes over time and space. 

The site was surveyed over the two-day period by assigning each surveyor a series of zones. Each 

zone was surveyed only once per survey; two days were needed to cover all of the zones. The surveys 

would have been discontinued for the day if wind, visibility, rain, or other factors were deemed to be 




unsuitable for accurate and effective data collection, including an absence of territorial behavior by the 

sparrows. No such problems were encountered during these two surveys. All survey data were 

initially recorded in the field on hard copy maps of each zone and then transferred in the office to GIS 

database files. 

The location of each Belding’s Savannah sparrow territory observed was plotted on a map based on the 

behavior observed which included: singing by a perched male, extended perching together of mates, 

territorial defensive behavior demonstrated by circular chasing of birds from a territory, scolding, 

carrying nesting material or food, feeding young, extended high and fully exposed perching of 

individuals, and scolding. All behaviors were marked on the field map of the zone being assessed. At 

the completion of the survey of each zone, the biologist reviewed the notes, assessed the significance 

of each behavior noted, and wrote down a tally of the total number of territories assessed in that zone. 

Biologists were careful to keep track of birds within a zone to avoid over counting territories and did 

not spend too much time in a particular zone to avoid confusion. The ranking of behavior used to 

determine a territory, listed from most-certain to least-certain, was: extended perching of a pair, 

singing male, territory by chase, and extended exposed perching by a male. If the biologist mapped a 

male as perched for an extended period of time, but it later began singing, the singing would supersede 

the perching in making the determination and the final map would show a single singing male. 

From these breeding and territorial behaviors, the number and approximate locations of territories 

within each zone were estimated. This method has been used by the U.S. Fish and Wildlife Service 

and California Department of Fish and Game when the scope of the surveys does not include precise 

determination of the number of territories present. This technique has been used for statewide surveys 

(Zembal et al., 2006). However, a clearly defined, written protocol for surveys of this type does not 

exist and there will therefore be some unavoidable variation in technique and judgment between survey 

programs. 

Results 

The location of the Belding’s Savannah sparrow territories estimated by the observed breeding and 

territorial behaviors is shown in Figure 1-19. A total of 177 territories were identified within the study 

site in April 2008 and 208 territories in May 2008. The majority of territories were determined by 

observation of a singing male (65%), followed by extended perching of pairs (14%), and extended 

perching by a male (12%), with the other behaviors making up roughly 9% of the territories 

determinations. Territories appeared to be relatively evenly dispersed throughout areas where 

pickleweed-dominated salt marsh occurred. Nearly all areas of non-flooded pickleweed that appeared 

to be of high quality but had no territorial birds in it were observed to be occupied by Belding’s 

Savannah sparrows, though they were engaged in non-territorial behaviors such as foraging or moving 

about in groups. 

The Future Full Tidal Basin supported the most territories, followed by the Muted Tidal Basins, then 

the Seasonal Ponds (Table 1-21). The number of territories did not correlate with the amount of salt 

marsh available. The number of territories recorded was about 50% of what was counted in 2007 and 

was similar to the count in 2006 (Zembal et al., 2006). The Seasonal Ponds supported 52%-59% of the 

territories in 2008 as it did in 2007. The salt panne in this area was flooded throughout the breeding 

season and in some cases this flooding also entered into areas of pickleweed. The FFTB also had 


Zone PM 2 9 10 11 12 13 14 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 38 39 40 41 42 45 46 47 48 49 50 63 66 68 Total 

Apr-08 2 10 10 8 14 4 7 4 4 5 2 2 2 1 2 0 2 1 1 6 2 4 7 5 3 1 1 6 7 10 6 6 7 2 6 4 3 4 1 5 177 

May-08 3 7 5 5 21 4 5 6 9 1 1 1 3 2 1 1 2 1 0 4 1 5 6 6 7 2 3 7 4 7 10 11 11 3 12 7 10 3 1 10 208 

PM 

50 

66 

47 

49 

48 

46 

68 

69 

45 

42 

41 

71 

40 

39 

38 

70 

30 

63 

37 

72 

29 31 

19 

28 

20 

14 

9 

32 

27 

21 

13 

33 

26 

25 

22 

34 

35 

24 

23 

36 

73 

10 

12 

2 

11 

April 21 and 22, 2008 (177 Territories) 

May 12 and 13, 2008 (208 Territories) 

0 100 200 400 600 800 

Meters 

Belding's Savannah sparrow territories - 2008 


Figure 1-19 




about half as many territories as in 2007. Zone 36 at the eastern end of the site is normally wet all 

year; but in 2008, this zone dried out and was apparently not as suitable for the sparrow. It supported 

19 territories in 2007 and only 2 in 2008. All other zones in the FFTB decreased by small numbers 

between 2007 and 2008. 

The counts in the MTB were the most variable, ranging from counts of 45 territories in April to 72 

territories in May, while having had a count of 117 territories in 2007. The west MTB (Figure 0-1) 

was opened to tidal influence from the FTB on March 5, 2008, which inundated much of the 

pickleweed growing at low elevations (in Zones 50, 66, and 49). In conjunction with rainfall, tidal 

waters flowing from the west to the central basin resulted in inundation of some low pickleweed in the 

central MTB as well (Zones 48 and some of 46). Belding’s Savannah sparrow were regularly 

observed defending territories that were inundated. 

Zones 41, 45, and 46 decreased from the 2007 counts by a minimum of 17 (63%), 14 (56%), and 9 

(45%) territories respectively. These zones are normally dry and covered in pickleweed and remained 

unchanged between the 2007 and 2008 breeding season. 

Using the area of undisturbed salt marsh available and the maximum number of territories recorded per 

cell over both surveys within Zones 2-29, the average territory size was estimated to be 1,836m 2 , 

ranging from 693 m 2 in Cell 26 to 3,714m 2 in Cell 9. This is a very course calculation and does not 

take into account the observed patchy distribution of the birds in the marsh or the considerable areas of 

what appeared to be suitable habitat that remained unoccupied. 

Table 1-21. Belding’s Savannah sparrow territories at Bolsa Chica in 2007 and 2008 

Zone 

# of Territories # of Territories # of Territories Salt Marsh 

April 2007 April 2008 May 2008 Available (ha) 

Full Tidal Basin n/a 5 10 5.0 

Future Full Tidal Basin 143 72 76 25.3 

Muted Tidal Basins 118 45 72 44.5 

Seasonal Ponds 90 53 47 11.6 

Pocket Marsh n/a 2 3 4.6 

Total 351 177 208 91.0 

n/a = not counted during 2007 

Discussion 

The count of Belding’s Savannah sparrow territories in 2008 was considerably lower than in 2007, but 

comparable to the counts (201 territories) in the 2006 annual survey conducted by CDFG (Zembal et 

al., 2006) within a similar area of Bolsa Chica. The 2007 increase may have resulted from a 

movement of birds out of the newly created FTB. Prior to inundation the area of the new FTB 

supported pickleweed-dominated salt marsh where Belding’s Savannah sparrow regularly nested and 

foraged. When the FTB was excavated and later opened to the ocean in August 2006, much of the 

pickleweed in that area was lost, which may have forced the sparrows to move the following year 

(2007) to more suitable habitat in the salt marsh and salt panne areas of the FFTB, MTBs, and in 

particular the Seasonal Ponds. 




The reduced number of territories documented in 2008 could be related the to extensive inundation of 

some cells by rainfall and tidal influence, though males were observed actively defending territories 

that were inundated throughout and did not have higher, dry areas that other territories near zone edges 

did. A clear trend between marsh inundation and usage by breeding birds was not observed. 

Considerable movement by the birds between zones was noted, particularly with birds leaving to 

forage for extended periods of time on the riprap, mudflat, and eelgrass of the FTB, likely resulting in 

missed documentation of territories. To compensate for this to some extent, the surveys during Year 2 

were conducted twice within the season. Although many individuals were mapped on the same 

territories between surveys, a large number of territories were only observed on one survey or the 

other, and there were 18% more territories on one date than the other. Examination of Figure 1-19 

shows that although the total number of territories was relatively similar, the physical distribution of 

territories between surveys was considerable in many locations. The most variable zones were located 

in the FTB and MTB, which had 50% and 60% more territories on one date than another, respectively. 

Zone 11 also had high variability and appeared to have a large number of territories in a small area. It 

is expected that this variability will continue in future counts; however, continuation of the two-survey 

approach may help provide a better picture of the range of usage of the site. It is also recommended 

that the surveys be conducted in late February and March to reduce further complications related the 

presence of dispersing juveniles. The Belding’s Savannah sparrow will normally return to their 

breeding grounds in January and start breeding by March. 

The density of territories of Belding’s Savannah sparrow at Bolsa Chica was low in comparison to 

assessments of territory size at other sites. In their study of 54 territories at Sweetwater Marsh in San 

Diego County, Powell and Collier (1998) found that territories ranged from 84.5m 2 to 999.5m 2 with an 

average of approximately 475m 2 . Massey (1979) measured territories at Anaheim Bay in Orange 

County that ranged between 250m 2 and 375m 2 at 14 territories. The estimation of territory size at 

Bolsa Chica is much larger (1,836m 2 ), however this calculation takes into account all available 

pickleweed habitat, including that which may not be occupied, and is therefore likely an overestimate. 

The birds were sometimes observed defending territories in very close proximity to each other. 

Several years of subsequent survey will need to be completed in order to better consider whether there 

is a general decline in usage of the site by Belding’s Savannah sparrows, or if 2008 was just a year of 

reduced nesting for other reasons. When the MTBs are fully operational with muted tidal connections 

to the FTB, much of these zones will be inundated daily, with the higher edges of the zones remaining 

dry. Future surveys will reveal the degree of usage these zone receive once they are tidal. 

The quality of habitat in the FTB is expected to improve over time, as pickleweed becomes better 

established at Rabbit Island and on the upper edge of the mudflats of the bench on the eastern shore. 

California Least Tern and Western Snowy Plover Monitoring 

Methodology 

California least tern nest monitoring occurred on North Tern Island (NTI), South Tern Island (STI), 

Nest Site 1 (NS1), Nest Site 2 (NS2), and Nest Site 3 (NS3) (Figure 0-1). NTI and STI are located in 

Inner Bolsa Bay, outside of the project survey area, but are included in this report in order to give a 

more complete understanding of tern reproductive success at the Bolsa Chica complex. NS1, NS2, and 

NS3 were created by the restoration project. NS1 is in the FTB bordering the FTB and Inner Bolsa 




Bay, NS2 is located within Zone 42 of the southern MTB, and NS3 is located in Zone 14 of the FFTB. 

Western snowy plover nest sites included all tern colonies listed above but also included the Seasonal 

Ponds (Zones 1 through 37). 

The principal survey effort for California least tern and western snowy plover was undertaken by 

CDFG seasonal staff member, Peter Knapp and assisted on NS1 by Kelly O’Reilly, CDFG. Merkel & 

Associates biologist, Bonnie Peterson, participated intermittently in the survey efforts as support and to 

aid in collecting data for report preparation. STI and NS1 were surveyed by vehicle from the West 

Levee Road prior to arrival of the least terns and then on foot. NTI was used primarily by nesting 

elegant terns and black skimmers and therefore required minimal monitoring for least terns and 

plovers. Observations were made from the West Levee Road. NS2 was surveyed by vehicle from the 

East Levee Road weekly using a spotting scope and once a month on foot. NS3 was surveyed by 

vehicle from the north end of the site. The large majority of suitable western snowy plover nesting 

habitat in the Seasonal Ponds was visible from the road network. The observer(s) would slowly drive 

along the roads that subdivide this area. Frequent stops were made to examine specific areas adjacent 

to the road with binoculars or spotting scope without exiting the vehicle. 

NS1, NS2, and NS3 are sectioned by markers, which form the basis for data recording. NS1 is 

sectioned south to north from A though CC in a regular grid. Each least tern and snowy plover nest 

located on NS1 was marked with a numbered tongue depressor and mapped for ease of relocation on 

subsequent visits. 

Beginning in late-March, surveys for nesting western snowy plovers were conducted at least twice a 

week, sometimes 4 or 5 times a week, until the beginning of September. Data collected included the 

gender of the incubating adult, length of incubation (days), number of eggs in the clutch, condition of 

the nest (e.g. signs of disturbance), and the fate of each nest (hatched, predated, or abandoned). Close 

examination of nests was usually conducted only once or twice per nest. As snowy plover nests were 

located they were protected by Mini-Exclosures (MEs), which were placed over the nest. 

Observations of snowy plover broods were made 3 to 5 days per week. It was usually possible to 

follow the movements and determine the fate of the chicks from each brood since there was sufficient 

dispersion over space and time to differentiate between broods. These regular brood observations were 

conducted to determine chick survival or fledgling production, as well as to detect movement between 

zones and use of specific zones for brood rearing. 

California least tern monitoring began as soon as the terns started arriving at Bolsa Chica in mid-April 

and continued until the terns fledged and left the breeding grounds in late August. The observers 

would walk active tern colonies and mark and record the section of all new nests. This activity 

typically occurred between 0800 and 1200 hours, 1 to 2 times per week. Observers would record any 

hatched, abandoned or depredated nests. Any signs of disturbance within the tern colonies were also 

recorded. At other times during the week, observations on the status of the colony were made from 

observation points outside of the colony. Observations of least tern chicks and fledglings were made 

every 1 to 2 days to determine hatching and fledging success. 

In 2008, monitoring of nests on NS1 was very difficult due to the large number of nesting birds besides 

the western snowy plover and California least tern, including elegant tern, black skimmer, royal tern, 

and Caspian tern. These species previously nested primarily on NTI. By the end of June, monitoring 




was ceased due to disruption of the nesting birds and their chicks. Most nest data was collected prior 

to that time; however, fledglings for both the California least tern and the western snowy plover on 

NS1 had to be estimated. 

Results 

California Least Tern 

The data from the 2008 California least tern breeding season at Bolsa Chica Ecological Reserve were 

provided by CDFG and are summarized in Marschalek (2008). 

In 2008, the California least tern arrived at 

Bolsa Chica on April 14 and were last 

observed on the site August 19, which was 

very similar to past years. The terns 

nested primarily on STI and NS1, although 

one unsuccessful nest was located on the 

Seasonal Ponds in Zone 11 (Table 1-22). 

The least tern did not utilize NTI, NS2, or 

NS3. The first nest was initiated on May 

19 on the STI nesting site. There were a 

total of 242 California least tern nests at 

Photo by Bonnie Peterson Bolsa Chica in 2008, only slightly higher 

than the 226 nests in 2007. The average 

California least tern on nest. 

clutch size was 1.8 eggs per nest. From an 

estimated 217 pairs, a total of 432 eggs were laid. Fledgling success for the 2008 season ranged from 

100-150 fledglings with a rate of 0.41 to 0.62 fledglings per nest. This is compared to 15 fledglings in 

2007 and a rate of 0.07 fledglings per nest. The first least tern fledgling was recorded on June 23. 

Table 1-22. 2008 California least tern reproductive success for each nesting location. 

Location Total Nests Nests Failed* 

Nests Hatched 

(# chicks) 

Fledglings 

Nest Site 1 184 25 159 (281) -- 

South Tern Island 57 2 55 (89) -- 

Seasonal Ponds 1 1 0 (0) 0 

Total 242 28 214 (370) 100-150 

California least tern nest predation was low at 19 nests (7.9% of all nests). Seven (2.9%) nests were 

abandoned prior to hatching, and one nest was lost to flooding. Black skimmer and the larger terns 

nested on NS1, an area where the California least tern had already established their nests. It is 

estimated that 19-26 least tern nests were subsequently lost through trampling by other terns and 

skimmers. In order to increase hatching success, where California least tern nests overlapped with the 

larger terns and black skimmer, nests were encircled with wire fences 20 cm high and 1m in diameter. 

The circular fences successfully protected the eggs from being trampled by larger birds. 

Three chicks were observed lost to depredation: one chick was lost to a red-tailed hawk and two chicks 

were depredated by ants. 




Western Snowy Plover 

The complete 2008 results for the western snowy plover breeding season at Bolsa Chica can be read in 

the annual report (Knapp and Peterson 2008)(Appendix 1-G). 

The western snowy plover initiated its first nest on March 17, 2008 and the last nest hatched on August 

9. The plovers nested on STI, NS1, NS3, and a number of zones within the Seasonal Ponds (Table 1- 

23). A total of 67 nests were located at Bolsa Chica. Four completed clutches were 2-egg clutches, 

while 61 were 3-egg clutches. The remaining 2 nests were depredated prior to nest completion. From 

the 193 total eggs laid, 174 chicks were produced. Two of the 67 total nest attempts were lost to 

predators, one on Zone 22 early in the season and one on NS1. These nests were depredated prior to 

placement of the mini-exclosure over the nest. The probable predators for these nests were corvid and 

gull, respectively. Three nests, one with 3 eggs and two with 2 eggs, were abandoned. These nests 

were located on STI, NTI, and Zone 19, respectively. Of the 174 total chicks produced in 2008, a 

minimum of 57 and a maximum of 109 chicks (32.8 to 62.6%) were estimated to have survived to 

fledge. 

The minimum fledgling estimate per nest (0.85) is slightly below the average (0.95) of the study years. 

The maximum estimate of fledglings per nest (1.62) would exceed the previous high of 1.47 in 2005. 

Of the 67 nests, 24 nests did not fledge chicks. Of the 19 known nests producing chicks but not 

producing fledglings, one brood was depredated by gulls and one brood by coyote. The remaining 17 

broods were most likely depredated by red-tailed hawk (STI) or American kestrel (Seasonal Ponds). 

There was potential for trampling of the chicks on NS1 due to overcrowding. 

Table 1-23. 2008 Western snowy plover reproductive success for each nesting location. 

Location Total Nests Nests Failed* 

Nests Hatched 

(# chicks) 

Fledglings 

Nest Site 1 37 1 36 (100) 33-83 

Seasonal Ponds: 20 2 18 (51) 18 

Cell 9 1 0 1 (3) 3 

Cell 10 3 0 3 (8) 1 

Cell 12 3 0 3 (8) 6 

Cell 19 4 1 3 (9) 3 

Cell 22 6 1 5 (15) 2 

Road 3 0 3 (8) 3 

Nest Site 3 5 0 5 (14) 3-5 

North Tern Island 1 1 0 (0) 0 

South Tern Island 4 1 3 (9) 3 

Total 67 5 62 (174) 57-109 




Photo by Peter Knapp 

Snowy plover nest on Nest Site 1 surrounded by elegant terns. 

The tight colonial style of nesting of the terns and black skimmer on NS1 did not exclude the snowy 

plover from any portion of the nesting area. However, it is suspected that their presence on NS1 had 

an effect on the overall reproductive success of the snowy plover once the nests hatched and the chicks 

left the protection of the ME. 

The number of nests on NS1 has increased quickly from 14 nests in 2006, the first year the site was 

available, to 36 in 2008. Reproductive success has remained consistent on NS1 with a fledge rate of at 

least 0.89 fledglings/nest. The increased usage of NS1 has been balanced out by a decreased use of the 

Seasonal Ponds. The reproductive success on the Seasonal Ponds was very low in 2007 at 0.28, 

increasing to 0.90 in 2008 even with suboptimal conditions. Some of the zones normally available for 

nesting remained flooded throughout the 2008 breeding season and therefore were unavailable for 

nesting plovers. 

Discussion 

Reproductive success at Bolsa Chica for the California least tern was high in 2008 compared to 2007; 

however, the fledgling rate is still lower than the highly successful years of 2005 and 2006. In 2007, 

the Bolsa Chica tern colony on NS1 was devastated by the trampling of nests by other nesting terns 

and black skimmer as well as high black-crowned night heron predation. In 2008, as in 2007, black 

skimmer, elegant tern, royal tern, and Caspian tern all nested on NS1. However, nest predation was 

minimal and trampling was minimized by placing wire fencing around least tern nests adjacent to or 

within the skimmer colonies. 

Reproductive success at Bolsa Chica for the western snowy plover increased in 2008 from a low in 

2007 and is comparable to prior years. Even though there were some problems and/or deterrents 

during the nesting season, the snowy plover was able to fledge between 0.85 and 1.62 fledglings/nest. 

It is suspected that the greatest chick loss on NS1 was due to trampling as a result of overcrowding on 

this nest site. Also, many of the zones in the Seasonal Ponds that had regularly been used for nesting 

in the past were flooded during the 2008 nesting season. The ability of the snowy plover to adapt to 

changes in flooding regimes in the Seasonal Ponds suggests that the plover has not reached its highest 

potential for nesting snowy plovers in this area. 




Management of the California least tern and western snowy plover nesting sites is expected to be 

adaptive due to enhancement of the Bolsa Chica area and the creation of new nesting and foraging 

areas. Management recommendations for 2008 were made to increase reproductive success and to 

enhance the newly created nesting sites (Knapp and Peterson, 2008) and are summarized below. 

There are currently at least 6 species nesting on NS1 including black skimmer, elegant tern, royal tern, 

Caspian tern, as well as the western snowy plover and California least tern. This high-density nesting 

may have some benefits but appears to be highly detrimental to least tern and snowy plover nests and 

chicks. This problem requires long-term management that would address overcrowding and its effect 

on listed species, as well as a review of monitoring methods that would minimize disruption of this 

large nesting colony. For the 2008 breeding season, roof tiles were placed on the site. This 

management aided in the increased survival of chicks on the site through protection from both 

predation and trampling. Increased cover on NS1 in the form of vegetation and debris would decrease 

least terns and snowy plovers chick exposure to predators, lowering predation and aiding in increased 

foraging areas for snowy plovers. NS2 is not used by any nesting avian species and NS3 is currently 

being utilized by the snowy plover. These sites need to be assessed to determine how they can be 

managed and for what species. Finally, there needs to be improved water management in the Seasonal 

Ponds. Several zones, normally utilized by the snowy plover for nesting, were not available in 2008 

due to seasonal flooding and subsequent poor drainage. 


• Increase cover on NS1 in the form of vegetation and debris. 

• Assess sites NS2 and NS3 to determine how they can be managed and for what species. 

• Improve water management in the Seasonal Ponds. 

1.7. NON-NATIVE INVASIVE SPECIES 

An awareness of the importance of tracking the arrival and spread of non-native species has increased 

in recent years, particularly with the discovery of the invasive non-native seaweed Caulerpa taxifolia 

in nearby Huntington Harbour and in Agua Hedionda Lagoon in San Diego County. Early detection of 

some species of invasive plants and animals may allow the opportunity for quick and economical 

response activities. These species may include non-native seaweeds such as Caulerpa spp., Sargassum 

filicinum, and Undaria pinnatifida, or terrestrial weed plants such as pampas grass or Arundo, as 

mentioned above. However, there are other non-native species that are already proliferating in 

regional coastal embayments and are likely to invade the tidal areas of Bolsa Chica at some point in the 

future. While options to restrict these species from Bolsa Chica are limited, keeping good records on 

the time of arrival and the degree of spread can be helpful for understanding the threat posed by these 

species to Bolsa Chica, as well as for the general body of knowledge about these species. 

During the 2008 monitoring several non-native marine species were observed. At least two non-native 

tunicate species were captured in the restoration areas: Styela plicata and S. clava. These species are 

common occurrences in southern California and both have been documented to impact native species 

of tunicate by competing with them for space or food, or by impacting the reproductive success of the 

native species by consuming the planktonic larvae before they settle. Both species were first found in 




July 2008, roughly two years after the basin was opened to the ocean, and occurred in the FTB, west 

MTB, and MPM. 

Other non-native invertebrates documented included the invasive oriental shrimp (Palaemon 

macrodactylus). This species is considered established in California, and Ricketts et al. (1968) 

proposed that this species was responsible for the disappearance of native species of shrimp Crangon 

spp. in some cases. It is generally thought to be introduced by ballast water releases, from which it 

spreads to surrounding estuaries planktonically. The Mediterranean mussel (Mytilus galloprovincialis) 

was first observed in the FTB during the first survey in October 2007, and was also found during every 

quarter in 2008. This non-native species is well established throughout California. 

The Japanese mussel (M. senhousia) is another non-native presumed to eventually arrive at Bolsa 

Chica. This species settles from the plankton onto soft substrate and can form dense mats of entangled 

fibrous threads. This mat and the thousands of mussels that can colonize per square meter can inhibit 

the feeding of native filter feeders and the spread of eelgrass. Although there is no evidence of dense 

mats having formed at this time at Bolsa Chica, their capture in the fishing nets in October 2007 and 

April and July 2008 indicates their presence in the FTB and Muted Pocket Marsh. Cordgrass and 

eelgrass transplanted from Upper Newport Bay and the Port of Los Angeles in August 2007 was 

observed to have M. senhousia in its roots prior to planting in Bolsa Chica. This species may have 

already arrived in the FTB through the settlement of planktonic larvae prior to the transplant of the 

cordgrass and eelgrass. There is no effective means to control this species, however it has been 

documented that dense, healthy eelgrass beds can inhibit the growth of M. senhousia (Allen and 

Williams, 2003). 

The non-native bryozoan Zoobotryon verticillatum was observed in July and October 2008 in the 

Muted Pocket Marsh and at Station 2, respectively. This species is also well established in southern 

California bays and estuaries. It can seasonally grow to great expanses that can reduce the density and 

vigor of eelgrass beds, and smother native flora and fauna. 

Japanese wireweed (Sargassum muticum) is a seaweed native 

to Japan that is widespread in Southern California bays, 

commonly found on rock, riprap, or other hard substrate. 

This brown alga has been documented to compete with and 

displace native species of seaweed and eelgrass by reducing 

light through shading. At Bolsa Chica in 2008, the seaweed 

has not yet colonized the riprap, rather was observed loose in 

the FTB. The holdfasts of the seaweed were secured to highly 

motile scallops (A. ventricosus), which were serving as minireefs 

for the S. muticum to settle onto and be transported by. 

It is likely that hard substrate within the basin will become 

Sargassum muticum attached to a scallop. 

colonized with S. muticum following future reproductive 

events by the population on the scallops. There are no feasible means to control or prevent 

colonization by S. muticum, nor is its potential biological impact clearly understood in southern 

California. Future field work will also look for Sargassum filicinum, a related species recently 

discovered in some southern California bays and estuaries, and at Catalina Island. 




Non-native vertebrates observed in 2008 at Bolsa Chica included the yellow-fin goby (the only nonnative 

fish documented) and several birds, including rock pigeon and great-tailed grackle (Quiscalus 

mexicanus). The grackle is an invading species from Sonora or southern Arizona and is breeding at 

Bolsa Chica. 

There are numerous non-native plant species in the wetlands of southern California, however the Bolsa 

Chica Lowlands are fortunate to be devoid of two of the most invasive and difficult species. There is 

little to no occurrence of the giant reed (Arundo donax) or pampas grass (Cortaderia selloana) within 

the study area. Any observations of these species will be immediately reported to CDFG for removal. 

Hottentot fig (C. edulis) is widespread in the system and is being removed by CDFG and volunteer 

hand labor as resources permit. Black mustard (Brassica nigra) is widespread on the road margins and 

along the northeast corner of the site. Seasonally timed herbicide application would benefit the control 

efforts for these species. 

In some areas, particularly along the northern and eastern boundary of the side, a few highly invasive 

terrestrial weeds were observed in the early stages of establishment. These include artichoke thistle 

(Cynara cardunculus) and castorbean (Ricinus communis). The size and distribution of these specific 

plants is quite limited, unlike the ice plant and mustard discussed above. Early removal or herbicide 

treatment of these individuals in spring, prior to release of seeds into the system, would be 

tremendously helpful in restricting their spread 

and may result in financial and labor saving by 

avoiding their widespread establishment, such as 

currently seen with the mustard and others. The 

California Invasive Plant Council recommends 

prompt removal or treatment of these species 

upon their discovery if possible. Also to note, 

Spanish false fleabane (Pulicaria paludosa) was Species to be targeted for removal during early stages of invasion. 

identified in Zone 38. 


• Employ seasonally timed herbicide application to benefit the control efforts of non-native plant 

species. 

• Conduct early spring removal or herbicide treatment of invasive terrestrial weeds, prior to release 

of seeds into the system. 

• Continue assault on Hottentot fig with more strategic seasonal timing of herbicide application. 




II. PHYSICAL MONITORING PROGRAM 

The physical monitoring program focuses on large-scale morphological changes of the system and 

tidal response to these changes. Principally this monitoring includes evaluation of inlet shoaling, 

coastal beach response to inlet conditions and sand loss to the inlet shoal, and tidal reaction to shoal 

development. The physical monitoring program is intended to monitor changes in relation to 

management needs, and to adaptively evaluate and recommend adjustment of maintenance and 

management triggers where appropriate to ensure health of the system and protection of coastal beach 

resources. 

2.1. INLET FLOOD SHOAL 

Introduction 

A newly constructed inlet to a tidally influenced system will typically interrupt longshore sediment 

transport and divert sediment both offshore (creating an ebb bar) and towards the tidal basin (creating a 

flood shoal). As the ebb bar forms, it affects the wave and current regime. This, in turn, causes the 

shoreline planform to evolve toward a new dynamic equilibrium condition. Similarly, the flood and 

ebb tidal currents moving through the inlet will build and shape a flood shoal in the interior of the tide 

basin. The configurations and sizes of the bars depend on the tidal prism of the basin, cross-sectional 

area of the tidal inlet, length of the jetties, tidal range, sediment characteristics, and longshore sediment 

transport rate. While complete equilibrium is rarely achieved, rates of change within the ebb bar and 

flood shoal typically diminish as the conditions around a new inlet stabilize. To limit early adverse 

impacts of ebb bar development on the shoreline processes, approximately 929,326 m 3 (1,214,579 y 3 ) 

of sand was placed as pre-fill to form the ebb bar at Bolsa Chica prior to opening of the inlet. This fill 

was placed to avoid the potential for the full ebb bar developing from available beach sand engaged in 

longshore drift; thus robbing the littoral cell of mobile sand supply. 

As beach sand migrates longshore, it is made available for capture by flood tides entering the Bolsa 

Chica FTB. Sand is moved into the system where it settles into a flood shoal. A portion of this sand is 

moved back to the beach with the ebbing tide while a portion of the sand remains trapped in the shoal 

deposits. As the flood shoal matures, it will begin to restrict ebbing tidal flow through the inlet. Tidal 

flow restriction will diminish or mute the full tidal range in the system relative to the tidal range that 

would exist without the flood shoal. Therefore, a monitoring, maintenance, and maintenance dredging 

plan was incorporated into the Bolsa Chica Lowlands Restoration Project and is being implemented as 

an essential component to the long-term health and viability of the system. 

The oversized inlet of Bolsa Chica was sized to accommodate the tidal prism of the FTB, the three 

MTBs, and the FFTB. From the time of opening and throughout 2007, only the FTB supplied tidal 

prism through the inlet. In February 2008, the West MTB was opened adding additional muted prism 

to the FTB. Other basins remained closed through the remainder of 2008. As a result of the oversizing 

of the inlet, tidal velocities through the inlet are too low to keep the channel between the jetties fully 

open and sedimentation has occurred in the inlet channel as would be expected. As additional tidal 

prism is added to the system, the inlet mouth will increase in cross-sectional area as it responds to the 

higher tidal velocity required to feed the system during tidal exchanges. 

The preliminary engineering studies (M&N 1999) done for the project predicted a flood shoal volume 

of 126,200 m 3 (165,000 y 3 ) at the end of the first year and a shoaling rate of 102,500 m 3 /year (134,000 




y 3 /year) for the second year after the inlet was to be connected to the ocean, for a total of 

approximately 230,000 m 3 (300,000 y 3 ) over the first two years. The predicted flood shoal location is 

illustrated in Figure 2-1. Investigations were completed to assess the true rate of shoal accretion and 

distribution pattern of flood shoal development. 

Full Tidal 

Basin (Phase I) 

Modeled Shoal Area 

Tidal Inlet 

Scale 1’’= 1,800’ 

Figure 2-1. Predicted flood shoal area (cited from M&N 1999) 

Methodology 

The rate and distribution of sand accretion in the FTB inlet has been assessed during the first two 

monitoring years on January 19, 2007, June 27, 2007, January 10, 2008, and July 1, 2008. After the 

January 2007 survey it became clear that a larger area needed to be surveyed to capture the extent of 

the shoaling, therefore all following surveys extended a considerable distance further to the north. A 

survey was also conducted on December 23, 2008 by the maintenance dredging contractor hired to 

remove the accumulated sand from the inlet during the 2008/2009 winter season. This survey was 

performed by the dredging contractor’s surveyor, CLE Engineering, Inc., and was intended to 

document the pre-dredge bathymetric condition. 

The surveys were conducted from a small survey vessel with sub-meter accurate differential global 

positioning system (dGPS) and a survey-grade SyQuest Hydrobox ® fathometer. Land surveying was 

conducted using a total station to complete areas that were too shallow to conduct hydrographic 

surveys during the various survey intervals. The bathymetric survey area was previously presented in 

Figure 1-1. The methodology for the CLE survey in December 2008 was comparable to that 

completed by M&A, as described above. The December 2008 survey area did not cover the western 




edge of the maintenance basin, therefore an additional survey was conducted by CLE to fill this gap on 

January 28, 2009. It was assumed that these data generally reflected the conditions in this area at the 

time of the December 23, 2008 survey, as this area is not an area of high deposition, nor erosion. 

Survey work reported in this report was conducted prior to the first maintenance dredging event, which 

occurred in early 2009 and which will be reported on in the next annual report. 

Data from the vessel-based bathymetric assessment were post-processed to correct for tidal elevations 

at the time of the survey, and the boat and shore data was used to develop bathymetric contour plots for 

the basin. These contour plots were aligned with a plot of the same area from the post-construction, 

pre-opening, contour data collected on August 20, 2006 that was provided by Moffatt & Nichol. 

To estimate the rate of sand influx in the FTB, a sediment assessment polygon encompassing the area 

of shoal formation was established. The changes in volume within this polygon over time were 

quantified, both between surveys and in comparison to the pre-opening conditions in August 2006. 

Results 

The contour plots for the pre-opening survey and the five post-opening surveys are presented in Figure 

2-2. A small shoal had formed in the inlet by January 2007 and continued to expand through 2007 and 

2008. The net volume of sediment (composed entirely of littoral sand) accreted within the assessment 

polygon was compared to the pre-opening conditions and is presented in Table 2-1. The net accretion 

takes into the account minor losses of sediment due to erosion. 

Table 2-1. Net increase in inlet sediment volume in comparison to pre-opening conditions. 

Survey date Net Sediment Accretion (m 3 ) 

August 2006 (pre-opening) 0 

January 2007 + 59,481 

June 2007 + 122,105 

January 2008 + 158,403 

July 2008 + 180,905 

December 2008 + 204,623 

The total rate of volume change from the basin opening in August 2006 to the December 2008 survey, 

roughly 28 months later, was approximately 240 m 3 /day. It is important to note, however, that this 

average rate does not represent the actual accretion per day, as deposition and erosion occurred 

throughout the period at an uneven rate. 

To examine this variable rate, the contour plots of each survey were compared to each other to quantify 

areas of erosion and accretion between surveys. These comparisons are presented graphically in 

Figure 2-3. Included in the figure is a table that tracks the accretion and erosion of sediment over time 

within the sediment assessment polygon. As anticipated, there was a large input of sand between the 

basin opening on August 24, 2006 and the first survey on January 19, 2007, with an average of 402 

m 3 /day. The influx rate then decreased between subsequent surveys, to an average of 134 m 3 /day in 

2008. 


August 2006 (pre-opening) 

January 2007 

Sediment 

Assessment 

Polygon 

June 2007 


m (NAVD) 

2.6 - 3 

2.1 - 2.5 

1.6 - 2 

1.1 - 1.5 

0.6 - 1 

0.1 - 0.5 

-0.4 - 0 

-0.9 - -0.5 

-1.4 - -1 

-1.9 - -1.5 

-3.8 - -2 


December 2008 

Full Tidal Basin inlet bathymetry 


Figure 2-2 


Aug06 to Jan07 

Jan07 to Jun07 

assumed 

no change 

assumed 

no change 

Sediment 

Assessment 

Polygon 

Jun07 to Jan08 

Jan08 to Jul08 

Jul08 to Dec08 

Erosion/Accretion (m) 

-2.6 - -2.4 -0.7 - -0.6 

-2.3 - -2.2 -0.5 - -0.4 

-2.1 - -2 -0.3 - -0.2 

-1.9 - -1.8 -0.1 - 0 

-1.7 - -1.6 0.1 - 0.2 

-1.5 - -1.4 0.3 - 0.4 

-1.3 - -1.2 0.5 - 0.6 

-1.1 - -1 0.7 - 0.8 

-0.9 - -0.8 0.9 - 1 

1.1 - 1.2 

1.3 - 1.4 

1.5 - 1.6 

1.7 - 1.8 

1.9 - 2 

2.1 - 2.2 

2.3 - 2.4 

Survey Range Time Erosion Accretion Net Influx Influx Rate 

day m 3 m 3 m 3 m 3 /day 

Aug06 - Jan07 148 -1,157 60,638 59,481 402 

Jan07 - Jun07 159 -11,412 55,543 44,131 278 

Jun07 - Jan08 197 -10,612 46,381 35,769 182 

Jan08 - Jul08 179 -9,828 32,480 22,652 127 

Jul08 - Dec08 167 -16,742 40,523 23,781 142 

Full Tidal Basin accretion and erosion comparisons between surveys 


Figure 2-3 




Figure 2-4 presents the net accretion rate graphically as net sediment accretion per month within the 

assessment area shown in Figure 2-1. Again, the averages do not represent the actual accretion per day 

or month, as field observations noted that deposition and erosion occurred over time at an uneven rate. 

15,000 

Net Accretion Rate (m 3 /month) 

10,000 

5,000 

12,139 m 3 /mo 

8,327 m 3 /mo 

5,419 m 3 /mo 

3,775 m 3 /mo 

4,247 m 3 /mo 

0 

Opening through 

Jan. 2007 

Jan. 2007 through 

June 2007 

June 2007 through 

Jan. 2008 

Jan. 2008 through 


July 2008 through 

Dec. 2008 

Figure 2-4. Net sediment accretion rate per month 

A grain size analysis of the sand accreted in the FTB inlet was conducted in June 2008 in anticipation 

of maintenance dredging activities scheduled for 2009. The shoal sediment was documented to be 

99% sand with minor components of fine gravel (shell hash) and silt/clay fractions (M&A 2008b). 

Discussion 

Flood shoal development within Bolsa Chica exhibited patterns typical of coastal wetland systems. 

Shoals develop as individual depositional fans along the primary flow alignment. As sediments are 

deposited, the resistance to flow along the channel increases and shoals continue to build until such 

time as the flows break out of the main channel and define a new primary channel. As a result of the 

continued process, the flood shoal builds as a series of teardrop shaped lobes running into the basin. 

These are subsequently modified by wave and current erosion as water moves past and across the 

deposited fan. The importance of this shoaling process is that it creates a regular depositional pattern 

through a process defined by unpredictable events. The shoaling by highly settleable sands follows a 

pathway along the principal coarse of flow with little lateral spread in footprint. As a result, quiescent 

waters that are outside of the higher velocity effective flow path may not receive sediment deposition 

and more linear shoals may develop in alignment with flow patterns. Terminal and lateral slopes of the 

flood shoal deposit are typically at or near the angle of repose for the clean sands (approximately 30-35 

degrees). 

The bathymetric assessment of the FTB inlet and numerous site visits indicated that the tidal inlet 

morphology and sediment depositional areas (inlet thalweg and flood shoal patterns) are highly 




dynamic due to dynamic tidal and sedimentation processes. The January 2007 survey showed that the 

inlet thalweg was in the middle of the inlet channel and the shoal was on the southeast side of the inlet 

channel as shown in Figure 2-2. This reflects the infancy state of the wetland geomorphology at that 

time, with sediment not yet having been deposited along the inside bank of the tidal inlet channel. 

The June 2007 survey shows sedimentation along the inside bank of the tidal inlet channel, with the 

channel being forced toward the outside bank. That pattern continued to evolve over time and is also 

reflected in the January, July, and December 2008 surveys. From mouth opening through December 

2008, each survey shows the flood shoal growing progressively larger, corresponding to a period of 

time when low tides in the tidal basin were becoming increasingly truncated and tides were becoming 

more muted. The effects of the shoaling on tidal muting are analyzed in Section 2.2. 

Also noted in the progression of surveys are a series of new channel cuts through the flood shoal as the 

resistance to tidal flow along the primary channel caused breakouts and new channel formation into the 

larger FTB basin. These breakout channels resulted in the expansion of the flood shoal to the west, 

away from the primary linear shoal accumulation and into the boat ramp area along the west shore to 

the north of the inlet. 

Another morphologic feature noted in the shoal formation was the generation of an elevated and shell 

fragment-armored nose on the inside radius of the inlet channel as it enters the FTB. This elevated 

shoal was the result of both current-transported and wave-built littoral sand accumulation. The 

subsequent winnowing of sand from this bar resulted in an armoring of the feature by shell fragments 

carried in the littoral sands. Because of the significant bar development, the channel thalweg was 

pushed off the tip of the bar towards the opposite bank and narrowed significantly. The narrowing of 

the flow resulted in significant bed scouring at the base of a riprap-armored nose on the opposite bank. 

The scour displaced sands below the riprap toe and resulted in some loss of bank protection at this 

location. As a result, rock was replaced at the toe of the riprap slope on the south side of the inlet to 

restore protection to this area. 

Based on the bathymetric assessments, it could be estimated that the flood shoal volume deposited 

during the first twelve months post-opening, August 2006 through July 2007, was approximately 

127,524 m 3 (166,667 yds 3 ) (derived by taking the 122,105m 3 surveyed in June of 2007 and adding 

5,419 m 3 (a single month times the average estimated deposition rate for the subsequent period, June 

2007 through January 2008). This method of annualizing the shoal volume would be expected to 

result in an underestimate of shoaling due to the generally declining shoaling rate through time. Using 

this estimating approach, the actual shoaling rate was estimated to be only 1% higher than the 126,200 

m 3 (165,000 yds 3 ) predicted as the first year shoal volume (M&N 1999). 

As expected, the subsequent sediment accretion rate shown in Figure 2-3 decreases gradually, as the 

flood shoal developed towards an equilibrium state. The second year shoaling rate from August 2007 

through July 2008 is roughly estimated at 53,381 m 3 /year (69,395 yds 3 /year) (derived by subtracting 

the estimated August 2007 volume from the July 2008 surveyed volume. This rate is substantially 

lower than the 102,500 m 3 /year (134,000 yds 3 /year) shoaling volume predicted by preliminary 

engineering modeling for the second year after the inlet was to be connected to the ocean (M&N 

1999). However, when taken as a whole, the model-predicted two-year accumulation volume of 

230,000 m 3 (300,000 yds 3 ) compares very favorable to the early period measurements and rate-based 

escalation two-year volume of 180,905 m 3 (237,000 yds 3 ) from the post-construction monitoring. The 




measured second year shoaling was thus determined to be 79% of that predicted by the preliminary 

engineering model calculations. 

The variable seasonal influx of sand, and added complication of provision of local source sand in the 

pre-filled ebb bar and beach around the mouth likely have played a role in the high early infill rates. 

Further, early infill would have also added sand to the oversized entrance channel, thus decreasing the 

observed rate of shoaling from the true rate since the flood shoal survey assessment area does not 

extend to the full extent of the entrance channel. Subsequent reduced rates of infill may illustrate more 

rapid achievement of relative stability following the initial system loading. The lack of temporal 

precision and high variance associated with early system dynamics is to be expected with limited 

predictive methods. 

Through 2008, the average monthly shoal accumulation rate remained remarkably stable with the 

average accumulation rate from January-June 2008 being 3,775 m 3 /month and July-December 2008 

being an average of 4,247 m 3 /month. The six-month accumulation rates, however, mask what are 

likely to be much more variable instantaneous rates that are dependent upon tide state, surf conditions, 

littoral transport volumes, and patterns of flow across at the flood shoal. Tidal monitoring in the FTB 

suggests that at least one punctuated change in the flood shoal may have occurred during 2008 (see 

Section 2.2). This may reflect the formation of a minor sill across the primary tidal channel, followed 

by a breach of the sill, or the cut of a new primary channel across the flood shoal. 

The flood shoal volume, area of shoaling, and shoaling rate have occurred similarly to processes 

predicted during the project design. The notable difference between predicted shoaling and that 

actually observed has been the bypass of much of the maintenance basin by the shoal formation and 

thus a greater penetration into the FTB than would be expected given the accretion volume manifested 

at this early period in shoal formation. Although ultimate shoal formation is expected to extend much 

further into the FTB (Figure 2-1), the early bypass of portions of the shoal maintenance basin allowed 

a more rapid progression of the shoal along the eastern edge of the basin than the western edge. In 

retrospect, this bypass should have been predictable given past observations of shoal development in 

systems such as Batiquitos Lagoon, Agua Hedionda Lagoon, and San Elijo Lagoon and the anticipated 

patterns of effective tidal flows. As the sand accumulation along the eastern edge of the basin 

develops a greater resistance to flows, the effective flow pattern is expected to shift into those portions 

of the maintenance basin that have not received sand accumulation, thus beginning to infill the full 

extent of the basin with shoal sands. 

Another principal difference in shoal development from that anticipated was the transverse bar 

development at the inside curve and the subsequent deep scouring on the opposite bank to the south. 

Given basin morphology, the observed development patterns of the Bolsa Chica flood shoal are 

anticipated to continue in the future. It is less clear how the future accretion rates will vary as the inlet 

conditions continue to evolve and respond to maintenance dredging, changes in littoral cell sand 

availability, coastal storm climates, and the addition of future prism with the opening of the remaining 

central and eastern MTBs. 

The manner in which the basin performs as expected or different from expected is a factor in 

determining the necessity for shoal dredging and the establishment of triggers. This is addressed in 

Section 3. 




2.2. TIDAL MONITORING 

Introduction 

Tidal monitoring is fundamental to understanding the factors influencing physical and biological 

structure of the Bolsa Chica Lowlands. As a non-estuarine system with minor surface freshwater 

input, oceanic tides combined with winds are the principal forces driving the hydrodynamics within the 

wetlands. Conversely, as these factors act to sculpt the physical and biological environments, feedback 

loops associated with alteration of basin bedform and shoreline conditions influence tidal conditions 

within the system. Ultimately, roughness associated with the development of vegetation will influence 

tidal conditions; presently, this is an inconsequential variable in assessing system conditions. 

At the present time, accretion and erosion of sand within the flood shoal of the FTB has the greatest 

impact on tidal conditions, resulting in tidal lag and muting. While it is anticipated that the future 

opening of the central and east MTBs (in addition to the west which was opened in Marsh 2008) will 

influence the shape of tidal curves in the FTB, it is expected that the principal factor influencing the 

performance of the entire system will be the tidal drain and fill parameters between the ocean and the 

FTB. 

The restoration and opening of the Bolsa Chica Lowlands to the Pacific Ocean allowed nearshore 

littoral sands to be drawn into the FTB, forming a flood shoal that restricts and retards tidal flows at the 

entrance of the FTB (refer to Section 2.1). Tidal monitoring provides a means of tracking the tidal lag 

and muting to provide information regarding the functionality of the system and the need for 

maintenance dredging. 

The tidal monitoring program also offers insight into intertidal mudflat and vegetative habitat 

development within intertidal elevation ranges. Tidal muting and loss of drainage affect inundation 

frequency within the intertidal zone that further affects oxidation-reduction potential in the sediments. 

These changes in tidal hydroperiods and associated factors can have substantial consequences on 

mudflats and marshland development. 

Methodology 

Tidal monitoring was begun in the FTB on December 21, 2006 at 11:06 and has been continuous since 

then with data collected at 6-minute intervals. The tidal data were collected with a RBR Instruments 

TGR2050 pressure gauge. The TGR2050 has a depth accuracy of ±5 mm and a resolution of ±0.1 mm. 

A second TGR2050 pressure gauge was deployed nearby, on shore and used to correct the submerged 

pressure gauge for atmospheric pressure. 

The pressure data obtained from the submerged and atmospheric pressure gauges were used to 

calculate water depth at the sensor with the following formula: 

Depth = (P w – P atm ) / (λ * 0.980665); 

where depth is the water depth in meters at the pressure gauge, P w is the pressure in deciBars read at 

the in-water pressure gauge, P atm is the local atmospheric pressure in deciBars, λ is the density of 

seawater measured at the study site (1.027 g/cm 3 ), and 0.980665 is a gravitational constant (RBR 

2007). 




The tide logger was held in an aluminum bracket mounted to the FTB bulkhead at the east water 

control structure. The initial bracket configuration resulted in a sensor elevation of –0.05 m NAVD. 

This elevation was not sufficient to capture the lower low tides during spring tidal cycles. On January 

19, 2007 at 13:00, the bracket was extended, resulting in a sensor elevation of –0.68 m NAVD. A 

subsequent elevational measurement of the FTB bulkhead by Coastal Frontiers resulted in adjustment 

of the sensor elevation to –0.72 m NAVD. This sensor elevation was used for data reported in the 

2007 annual report. In 2008, it was learned that nearby Orange County elevational benchmarks had 

been adjusted 7 cm to account for local subsidence. Thus, the tide stations sensor elevation was 

corrected to –0.79 m NAVD. This change, along with a minor calculation error discovered during 

analysis of the 2008 data, resulted in minor changes to previously reported values. When appropriate, 

these corrections are provided in the below text. 

Tidal elevations were calculated by adjusting the 6-minute water depth data with the sensor elevation. 

The tidal muting analyses are based on data collected from January 20, 2007 through December 31, 


Recorded tides were compared with tides measured at the nearest tidal station, located 22.5 km (14 

miles) north in Los Angeles Outer Harbor (LAOH) (NOAA Station 9410660). The NOAA gauge is 

located immediately adjacent to the open ocean, and the recorded tides represent the ocean tidal 

conditions. The data were obtained from the NOAA Tides and Currents website 

(http://tidesandcurrents.noaa.gov). The obtained data were not temporally corrected based on distance 

to the study site because the correction is less than the logging period. 

Results 

Comparison of the lower low tide data for each sampling date since January 20, 2007 against the 

NOAA tide data for LAOH shows that the FTB does not completely drain to local oceanic sea levels 

during lower low spring tides (Figure 2-5a). Moreover, the data indicate that tidal muting trends 

observed in 2007 were continued and became more pronounced during 2008. In 2008, lower low tides 

in the FTB only went as low as LAOH during very mild neap tides. 

Plotting the differences between the minimum observed tidal elevations for all daily lower low tides at 

LAOH versus the FTB numerically illustrates increased tidal muting (Figure 2-5b). From January to 

December 2007, tidal muting within the FTB had increased by an average of 0.07 m (previously 

reported as 0.10 m). Muting accelerated during 2008. By the end of 2008, tidal muting averaged 

approximately 0.40 m. The maximum low tide differential between LAOH and the FTB was 0.86 m 

on July 2, 2008. Notably, on infrequent occasions the tidal elevation of the ocean tides marginally 

exceeded the elevation within the FTB. This occurred principally at periods of neap tide and may be 

the result of a variety of factors including inlet morphology, tidal lag influences, or instrument variance 

at particular times. 

Table 2-2 summarizes the bi-weekly spring highest and lowest tidal elevations observed in the FTB 

and LAOH. Because the FTB gauge was lowered on January 19, 2007 only a partial spring-neap tidal 

cycle was analyzed for the first cycle in January 2007. The column identified as “Difference” under 

“Spring High Tide” show the spring high tide differences as calculated by subtracting the highest tide 

in the FTB by that at LAOH. A negative number indicates that the ocean high tide is higher than that 

in the FTB, and a positive number indicates the FTB has a higher high tide than that in the ocean. The 

general change from slightly positive values in 2007 to negative values in 2008 may be associated with 




0.8 

0.6 

FTB 

LAOH 

Daily Minimum Tidal Elevations 

Lower Low Tide (m NAVD) 

0.4 

0.2 

0.0 

-0.2 

-0.4 

-0.6 

-0.8 

Jan-2007 

Feb-2007 

Mar-2007 

Apr-2007 

May-2007 

Jun-2007 

Jul-2007 

Aug-2007 

Sep-2007 

Oct-2007 

Nov-2007 

Dec-2007 

Jan-2008 

Feb-2008 

Mar-2008 

Apr-2008 

May-2008 

Jun-2008 

Jul-2008 

Aug-2008 

Sep-2008 

Oct-2008 

Nov-2008 

Dec-2008 

Date 

Figure 2-5a. Minimum daily tidal elevations in the Bolsa Chica Full Tidal Basin (FTB) and at the Los Angeles 

Outer Harbor (LAOH) between January 20, 2007 and December 31, 2008 (Values are measured, lower low 

tide in meters NAVD88) 

1.0 

Daily Minimum Tide Differences (Bolsa FTB minus LAOH) 

0.8 

Difference (m) 

0.6 

0.4 

0.2 

0.0 

-0.2 

Jan-2007 

Feb-2007 

Mar-2007 

Apr-2007 

May-2007 

Jun-2007 

Jul-2007 

Aug-2007 

Sep-2007 

Oct-2007 

Nov-2007 

Dec-2007 

Jan-2008 

Feb-2008 

Mar-2008 

Apr-2008 

May-2008 

Jun-2008 

Jul-2008 

Aug-2008 

Sep-2008 

Oct-2008 

Nov-2008 

Dec-2008 

Date 

Figure 2-5b. Daily differences in lower low tide elevations between the FTB and the LAOH (Values are in 

meters with negative values indicating lower tidal values in the Bolsa Chica FTB and positive values indicating 

lower tidal values at LAOH. The straight line represents the trend in the daily differences over the dates 

observed) 




Table 2-2. Summary of spring high and low tides (m, NAVD). 

Spring‐Neap Tide Spring High Tide (m, NAVD) 

Spring Low Tide (m, NAVD) Tidal Range (m) 

Cycles 

Date LAOH FTB Difference Date LAOH FTB Difference LAOH FTB 

Jan 1 ‐ Jan 10 2007/01/02 2.072 2.096 0.024 2007/01/02 ‐0.481 ‐0.12 0.361 2.553 2.216 

Jan 11 ‐ Jan 25 2007/01/19 1.97 2.012 0.042 2007/01/18 ‐0.507 ‐0.208 0.299 2.477 2.22 

Jan 26 ‐ Feb 9 2007/01/31 1.959 1.974 0.015 2007/02/01 ‐0.427 ‐0.198 0.229 2.386 2.172 

Feb 10 ‐ Feb 24 2007/02/17 1.869 1.865 ‐0.004 2007/02/16 ‐0.593 ‐0.35 0.243 2.462 2.215 

Feb 25 ‐ Mar 11 2007/02/28 1.583 1.634 0.051 2007/02/28 ‐0.491 ‐0.222 0.269 2.074 1.856 

Mar 12 ‐ Mar 26 2007/03/21 1.858 1.863 0.005 2007/03/17 ‐0.449 ‐0.232 0.217 2.307 2.095 

Mar 27 ‐ Apr 9 2007/04/05 1.578 1.567 ‐0.011 2007/03/28 ‐0.298 ‐0.132 0.166 1.876 1.699 

Apr 10 ‐ Apr 25 2007/04/18 1.931 2.04 0.109 2007/04/18 ‐0.542 ‐0.17 0.372 2.473 2.21 

Apr 26 ‐ May 10 2007/05/03 1.675 1.773 0.098 2007/05/03 ‐0.263 ‐0.025 0.238 1.938 1.798 

May 11 ‐ May 24 2007/05/16 2.005 2.046 0.041 2007/05/18 ‐0.638 ‐0.271 0.367 2.643 2.317 

May 25 ‐ Jun 8 2007/06/01 1.783 1.834 0.051 2007/06/02 ‐0.329 ‐0.118 0.211 2.112 1.952 

Jun 9 ‐ Jun 23 2007/06/14 2.112 2.148 0.036 2007/06/15 ‐0.534 ‐0.209 0.325 2.646 2.357 

Jun 24 ‐ Jul 6 2007/06/30 1.893 1.931 0.038 2007/07/01 ‐0.362 ‐0.123 0.239 2.255 2.054 

Jul 6 ‐ Jul 21 2007/07/13 2.035 1.961 ‐0.074 2007/07/13 ‐0.531 ‐0.316 0.215 2.566 2.277 

Jul 22 ‐ Aug 5 2007/07/29 2.093 2.055 ‐0.038 2007/07/29 ‐0.319 ‐0.124 0.195 2.412 2.179 

Aug 5 ‐ Aug 19 2007/08/11 1.964 2.023 0.059 2007/08/11 ‐0.384 ‐0.091 0.293 2.348 2.114 

Aug 19 ‐ Sep 3 2007/08/27 1.9 1.959 0.059 2007/08/28 ‐0.364 ‐0.039 0.325 2.264 1.998 

Sep 4 ‐ Sep 18 2007/09/08 1.784 1.82 0.036 2007/09/08 ‐0.248 ‐0.016 0.232 2.032 1.836 

Sep 19 ‐ Oct 3 2007/09/29 1.984 2.014 0.03 2007/09/25 ‐0.203 0.083 0.286 2.187 1.931 

Oct 4 ‐ Oct 18 2007/10/13 1.638 1.592 ‐0.046 2007/10/06 ‐0.103 0.084 0.187 1.741 1.508 

Oct 19 ‐ Nov 3 2007/10/26 2.075 2.124 0.049 2007/10/27 ‐0.51 ‐0.033 0.477 2.585 2.157 

Nov 4 ‐ Nov 18 2007/11/11 1.735 1.78 0.045 2007/11/10 ‐0.197 0.04 0.237 1.932 1.74 

Nov 19 ‐ Dec 2 2007/11/25 2.126 2.17 0.044 2007/11/25 ‐0.634 ‐0.12 0.514 2.76 2.29 

Dec 3 ‐ Dec 16 2007/12/10 1.868 1.84 ‐0.028 2007/12/08 ‐0.283 ‐0.07 0.213 2.151 1.91 

Dec 16 ‐ Dec 31 2007/12/24 2.085 2.09 0.005 2007/12/22 ‐0.682 ‐0.2 0.482 2.767 2.29 

Jan 1 ‐ Jan 15 2008/01/07 1.907 1.973 0.066 2008/01/08 ‐0.404 ‐0.097 0.307 2.311 2.07 

Jan 15 ‐ Jan 29 2008/01/21 2.013 2.018 0.005 2008/01/21 ‐0.683 ‐0.174 0.509 2.696 2.192 

Jan 30 ‐ Feb 12 2008/02/06 1.726 1.69 ‐0.036 2008/02/06 ‐0.515 ‐0.174 0.341 2.241 1.864 

Feb 13 ‐ Feb 27 2008/02/19 1.894 1.876 ‐0.018 2008/02/19 ‐0.475 ‐0.14 0.335 2.369 2.016 

Feb 29 ‐ Mar 13 2008/03/05 1.694 1.66 ‐0.034 2008/03/06 ‐0.402 ‐0.039 0.363 2.096 1.699 

Mar 14 ‐ Mar 29 2008/03/17 1.529 1.535 0.006 2008/03/18 ‐0.417 ‐0.05 0.367 1.946 1.585 

Mar 30 ‐ Apr 14 2008/04/07 1.875 1.864 ‐0.011 2008/04/08 ‐0.422 0.046 0.468 2.297 1.818 

Apr 15 ‐ Apr 29 2008/04/20 1.597 1.583 ‐0.014 2008/04/21 ‐0.249 0.2 0.449 1.846 1.383 

Apr 30 ‐ May 13 2008/05/05 2.008 1.994 ‐0.014 2008/05/07 ‐0.576 0.157 0.733 2.584 1.837 

May 14 ‐ May 28 2008/05/21 1.838 1.912 0.074 2008/05/20 ‐0.235 0.282 0.517 2.073 1.63 

May 29 ‐ Jun 12 2008/06/03 2.143 2.098 ‐0.045 2008/06/04 ‐0.6 0.218 0.818 2.743 1.88 

Jun 13 ‐ Jun 26 2008/06/18 1.831 1.818 ‐0.013 2008/06/18 ‐0.237 0.308 0.545 2.068 1.51 

Jun 27 ‐ Jul 10 2008/07/02 2.215 2.198 ‐0.017 2008/07/02 ‐0.532 0.326 0.858 2.747 1.872 

Jul 11 ‐ Jul 25 2008/07/17 1.921 1.874 ‐0.047 2008/07/17 ‐0.202 0.295 0.497 2.123 1.579 

Jul 26 ‐ Aug 8 2008/07/31 2.229 2.216 ‐0.013 2008/07/31 ‐0.431 0.327 0.758 2.66 1.889 

Aug 9 ‐ Aug 22 2008/08/15 1.89 1.883 ‐0.007 2008/08/16 ‐0.138 0.345 0.483 2.028 1.538 

Aug 23 ‐ Sep 6 2008/08/28 2.087 2.067 ‐0.02 2008/08/29 ‐0.323 0.363 0.686 2.41 1.704 

Sep 7 ‐ Sep 21 2008/09/18 1.858 1.835 ‐0.023 2008/09/13 ‐0.029 0.434 0.463 1.887 1.401 

Sep 22 ‐ Oct 6 2008/09/25 1.762 1.75 ‐0.012 2008/09/26 ‐0.128 0.368 0.496 1.89 1.382 




settlement of the East MTB water control structure (WCS) on which the FTB tide gauge is mounted. 

As this structure settled downward, it suggested a rising water elevation in the FTB and thus the 

subtracted difference from LAOH tide station data would indicate negative values. This artifact in the 

data is an order of magnitude less important than the measured muting rates within the FTB, but it is 

important to understanding sources of tidal measurement error at the site. 

The overall differences in the high tide elevations are relatively small as shown in Table 2-2, with a 

2007-2008 average difference of less than 0.007m. Given the anticipated settlement of WCSs, and thus 

the attached FTB gauge and the relatively minor variation from LAOH it is clear that no consequential 

muting of the high tides within the FTB has occurred. 

When examining the maximum spring tide muting that occurs at low tide on a spring-neap tidal cycle 

basis, the severity is much more pronounced than is evidenced during mean low tides or higher low 

tides. Table 2-2 also presents the low spring tide muting in the FTB in comparison to oceanic 

conditions at LAOH. This was calculated by subtracting the spring low tide in the FTB from the 

equivalent oceanic low tide at the LAOH gauge. When the low tide muting is graphed as a function of 

time (Figure2-6) several aspects of the FTB muting are revealed. First, the data indicate the presence 

of seasonal variation in muting, with an increase in the winter and mid-summer months when larger 

than average tidal ranges occur, and decreased muting during the spring and fall months when smaller 

than average tidal cycles occur. Figure 2-6 also shows fairly substantial changes in muting rates 

between months, including a relatively precipitous acceleration in the extent of muting in the system 

overall beginning in January 2008. Prior to that month, little change in the extent of muting was seen. 

After January 2008, there was a sharp increase in muting through approximately April 2008 after 

which time the spring tide low tide muting remained fairly constant through the remainder of the year. 

1 

0.9 

0.8 

Spring Tide Low Tide Muting (m) 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

Nov-06 

Dec-06 

Jan-07 

Feb-07 

Mar-07 

Apr-07 

May-07 

Jun-07 

Jul-07 

Aug-07 

Sep-07 

Oct-07 

Nov-07 

Dec-07 

Jan-08 

Feb-08 

Mar-08 

Apr-08 

May-08 

Jun-08 

Jul-08 

Jul-08 

Aug-08 

Sep-08 

Oct-08 

Nov-08 

Dec-08 

Jan-09 

Feb-09 

Figure 2-6. Maximum spring low tide muting (Muting reflects the maximum difference between the FTB and 

corresponding LAOH low tides) 




Plots of tidal elevations within the FTB and LAOH over this time period between December 21, 2006 

and December 31, 2008 are presented on a monthly basis for the entire data set in Appendix 2-A. 

Figure 2-7 shows a tidal comparison of February 2007, six months after the inlet was connected to the 

ocean in August 2006. 

Figure 2-7. Example comparison of recorded tides (February 2007) at FTB with the ocean tides (LAOH). 

By analyzing the tidal records for the FTB and LAOH, it is possible to determine the phase lag for low 

tide drain-out from the FTB. As shown in Appendix 2-A, there is no discernable phase lag between 

the high tides in the basin and those in the ocean. The lag of the low tide in the FTB compared to that 

in the ocean was approximately 78 minutes on January 19, 2007, 114 minutes on January 21, 2008, 

and 288 minutes by December 13, 2008. 

Discussion 

The preliminary engineering studies (M&N 1999) predicted a maximum tidal range of 2.286 m and a 

low tide muting of 0.213 m in the FTB under the post-construction condition. The tidal monitoring 

started on December 21, 2006 so there are no tidal records available for the immediate postconstruction 

condition (August 26, 2006 through December 20, 2006). The recorded spring low tides 

records were truncated before January 19, 2007 as described in the tide monitoring methodology. The 

FTB experienced a tidal range of 2.22 m and a low tide muting of 0.30 m in January 19, 2007. The 




recorded tides were very close to the predicted values of the post-construction condition. By January 

2008, the FTB experienced a tidal range of 2.19 m and a low tide muting of 0.51 m. 

The winter of 2007-2008 marked a considerable change in the tidal range and low tide muting within 

the FTB (Figure 2-6). From December 2007 through April 2008, tidal range decreased by 

approximately 0.24 m and tidal muting increased by an equivalent amount. From May 2008 through 

the remainder of the year, muting and tidal range remained fairly consistent with little additional 

muting being evidenced. By the end of 2008, the tidal range within the FTB had been reduced from 

that of the open coast by an average of approximately 0.6 m with the maximum observed range loss 

reaching 0.86 m during July 2008. 

It was expected that the tidal range would gradually decrease and muting of the low tide would 

increase over time. It was further expected that muting and phase lag would become more severe due 

to effects of flood shoal development in the FTB until the implementation of the first dredging event, 

occurring in 2009. Preliminary engineering predictions of the effect of shoaling on tidal muting were 

that the tide range would reach 2.256 m and muting of the low tide to reach 0.244 m (M&N 1999). 

Generally, the muted tidal range under the post-construction condition met the target of the “full tidal 

range” objective of the project planning documents during 2007, but with further shoal development in 

2008 the range substantively diminished, with the most distinct changes occurring during the 2007-08 

winter and spring months. Additionally, the low tide lag increased by only 36 minutes throughout 

2007. Over 2008, the increase in lag was 174 minutes, a nearly five-fold increase. 

During preliminary engineering, tidal predictions were based on a theoretical average spring tidal 

condition, not the maximum spring tide condition noted in the muting analysis (Table 2-2). Because of 

the high importance of the low tide muting and lag to the drain-fill hydraulics of the MTBs, these 

maximum drain-out conditions are of key interest as they pertain to proper functioning of the MTBs. 

Although the FTB would still be considered fully tidal in 2008, the diminishing drainage from the 

basin reached such a point as to restrict drainage from the open west MTB. The MTB tidal conditions 

are strongly influenced by the amount of stored water in them as a result of prior tidal history. Waters 

step up in elevation during moderate neap tidal series in the FTB and drain down during the more 

extreme low water levels of spring tide series. This un-natural tidal fill and drain pattern is required to 

provide gravity driven muted tides to marshlands that are located at elevations well below mean sea 

level. 

The west MTB was opened to the FTB in March 2008. During the first few months post-opening, 

adjustments were made to maximize tidal range in the basin. In October 2008, the gates were 

readjusted to restrict tidal flows into the west MTB due to increasingly inadequate drain-out during 

low tides. As a result of the loss of low tide range in the FTB, low water elevations slowly built to 

higher base elevations in the west MTB, causing the high water elevations to exceed desired maximum 

operating elevations. This caused intermittent overtopping the precautionary oil containment weir at 

the water control structure, and spilling over the lowered spillway that connects the west MTB to the 

central MTB. 

Although the Freeman Creek water control structure slide gates remained closed during 2008, the 

muting of the FTB would have otherwise restricted the full drain-out potential if they had been open, 

since the drainage of Freeman Creek is by gravity to the FTB. FTB water levels were higher than the 

creek in 2008 and would have precluded proper drainage. 




As a result of the shoal-associated muting and its controlling influence on the functioning of the MTBs 

and Freeman Creek, along with other variables (shoal volume and area of low intertidal habitat lost), 

maintenance dredging was warranted in 2008 and first scheduled to occur in the fall of 2008. 

In the “Statements of Interest for the Environmental and Beach Profile Monitoring of the Bolsa Chica 

Lowlands Restoration Project”, a dredging trigger was proposed as follows: “a tidal muting of the 

average low tide elevations (Mean Low Water) on the order of 0.5 feet would indicate that the flood 

shoal maintenance dredging was warranted”. This should be revised since the Mean Low Water in the 

FTB is unlikely to ever be muted prior to failing of the required MTB and Freeman Creek drain-out 

conditions. The spring low tide would be a more appropriate parameter to gauge the muting in the 

FTB. 

While water quality conditions and habitat function within the FTB remained high during all periods of 

2007 and 2008, the operational restrictions within the west MTB and increasing base water levels in 

the MTB affect vegetation condition and distribution, as well as tidal circulation. Both of these have 

the potential to significantly affect habitat functions. As a result, an appropriate maintenance dredging 

trigger related to impacts to tidal drainage from the MTBs should be included to optimize overall 

system functioning. This is addressed in Section 3. 

2.3. BEACH MONITORING 

Introduction 

The objective of the beach monitoring program is to develop a quantitative understanding of changes 

in the condition of the beaches adjacent to the newly constructed Full Tidal Basin (FTB) entrance 

channel. The study area includes portions of the Bolsa Chica and Huntington Cliffs shorelines. The 

monitoring program, which commenced in January 2007, is comprised of semi-annual beach profile 

surveys and monthly beach width measurements at seven sites located along a 5.3 km section of 

coastline between Bolsa Chica State Beach and 17 th Street in Huntington Beach. Coastal Frontiers 

Corporation conducted the beach profile surveys, while Moffatt and Nichol performed the beach width 

measurements. The historical research and collected data analysis was conducted by Coastal Frontiers 

Corporation. 

Figure 2-8 shows the locations of the beach profile transects used in the monitoring program. Two of 

these were established specifically for the monitoring program and were first surveyed in January 

2007. Five of the transects had been established previously and were included in the Coast of 

California Storm and Tidal Waves Study for the Orange County Region (CCSTWS-OC) conducted by 

the U.S. Army Corps of Engineers (USACE 2002). 

Transect establishment/recovery activities were conducted prior to the commencement of the initial 

beach profile survey. The initial beach profile survey for the Bolsa Chica Lowlands Restoration 

Project was conducted in January 2007. Additional surveys have been performed during each of the 

subsequent May and October time periods in 2007 and 2008 (Appendix 1-A). The monthly beach 

width measurements commenced in January 2007. The monitoring activities were detailed previously 

by Coastal Frontiers (2007a, 2007b, 2008a, 2008b, 2009) and are discussed under the methodology 

section below. 




Beach profile plots accompany this report in Appendix 2-B. Summary tables and figures are 

interspersed with the text, while supporting data are provided in Appendices 2-C, 2-D, 2-E, and 2-F. 

Historical Background Information 

The Bolsa Chica study area is contained within the Huntington Beach littoral cell, which spans the 

shoreline from the East Jetty of Anaheim Bay to the Newport Harbor Entrance. The area has been 

studied extensively as part of the CCSTWS-OC (USACE 2002) and in prior federal studies. 

Prior to significant coastal development, sand was delivered to the littoral cell from the San Gabriel 

and Santa Ana Rivers, with modest input from coastal bluff erosion. The littoral transport regime 

changed substantially following construction of the Long Beach/Los Angeles Harbor Complex, the 

jetties at Anaheim Bay (for the U.S. Navy Weapons Station, Seal Beach), and numerous flood control 

measures. Coastal erosion was particularly severe in Surfside-Sunset Beach and West Newport Beach. 

Figure 2-8. Location map 




In response to the loss of private and public property caused by erosion, the U.S. Army Corps of 

Engineers, in concert with the State of California and the County of Orange, has undertaken periodic 

beach nourishment operations in the Huntington Beach cell since 1964. The majority of the sand 

nourishment has been placed at Surfside-Sunset Beach, immediately upcoast of the Bolsa Chica study 

area. Table 2-3 summarizes the beach nourishment history at Surfside-Sunset Beach. The next 

nourishment episode (Stage 12) is planned for winter/spring 2009. 

The beaches along the Bolsa Chica study area benefited as the downdrift recipient of the Surfside- 

Sunset nourishment material. During the 34-year period between 1963 and 1997, the beaches 

advanced at four of the five historical transects included in the Bolsa Chica monitoring program. 

Mean sea level (MSL) shoreline advance ranged from 14 m at Transect 423+89 to 71 m at Transect 

350+71. The only occurrence of shoreline retreat during the 34-yr period was a loss of 18 m at 

Transect 378+28, located at Huntington Cliffs. The volume of sand above MSL increased in parallel 

to the beach width changes during the period. The shorezone volumes in the study area, which 

incorporate the sediment changes further offshore, increased at all of the sites. The greatest gains 

typically occurred prior to 1978 (USACE, 2002). 

Table 2-3. Beach nourishment history. 

Date Placement Site Borrow Site Volume (m 3 ) 

1964 Surfside/Sunset (Stage 1) Naval Weapons Station 3,058,000 

1971 Surfside/Sunset (Stage 4) Naval Weapons Station 1,728,000 

1979 Surfside/Sunset (Stage 7) Nearshore Borrow Pit 1,257,000 

1983 Surfside/Sunset (Stage 8) Naval Weapons Station 382,000 

1984 Surfside/Sunset (Stage 8) Nearshore Borrow Pits 1,147,000 

1984 Surfside/Sunset (Stage 8) Naval Weapons Station 497,000 

1988 Surfside/Sunset Naval Weapons Station 138,000 

1990 Surfside/Sunset (Stage 9) Nearshore Borrow Pits 1,393,000 



Source: USACE, 2002; Mesa, 2008a 

Historical Shoreline Data 

Historical shoreline data were used to provide context for the results of the current Bolsa Chica 

monitoring program. The available beach profile and beach width measurement data are summarized 

below. 

Historical Beach Profile Data 

As indicated above, five of the beach profile transects used in the Bolsa Chica monitoring program 

were included in the CCSTWS-OC. The study incorporated data from 18 beach profile surveys 

conducted between 1963 and 1997. The U.S. Army Corps of Engineers conducted an additional beach 




profile survey of the area in March 2002. More recent shoreline data are available from several Light 

Detection and Ranging (LIDAR) surveys commissioned by the Scripps Institution of Oceanography. 

These data were used to provide historical context for the results of the current Bolsa Chica monitoring 

program. 

The survey data used in the CCSTWS-OC for the period 1963-1995 were retrieved from the archives 

maintained by the Scripps Institute of Oceanography. The 1997 and 2002 survey data were obtained 

from the Coastal Frontiers Corporate archives. LIDAR data for October 2005 and March 2006 were 

retrieved from archives maintained by NOAA (NOAA 2008). 

The beach profile data used in the CCSTWS-OC are summarized in Figure 2-9. The historical surveys 

are not uniform with respect to profile location or areal extent. The U.S. Army Corps of Engineers in 

support of the Surfside-Sunset nourishment program, navigation channel deepening at Anaheim Bay, 

or the CCSTWS-OC, performed most of the surveys. The transect locations differ among surveys due 

Surfside-Sunset Bolsa Chica Huntington Cliffs Huntington Beach West Newport 

0 10000 20000 30000 40000 50000 60000 70000 80000 

0 

May-63 

2 Jul-64 

Oct-66 

4 Apr-69 

May-73 

6 Dec-78 

Jul-79 

8 Apr-82 

Jan-83 

0 Feb-92 

May-92 

2 Nov-92 

May-93 

4 Oct-93 

Apr-94 

6 Oct-94 

May-95 

8 Nov-97 

0 

Station (feet) 

Surveyed Transect 

CCSTWS-OC Transect 

Figure 2-9. Beach profile data used in CCSTWS-OC 

CCSTWS-OC Transect 

used in Bolsa Chica 


to the scope of each project and the perceived needs at the time of each survey. Only the profile data 

obtained between 1992-1997, and more recently in March 2002, are coincident with the transect 

locations used in the CCSTWS-OC. 

In order to allow a comprehensive analysis based on the direct comparison of successive profiles at 

fixed locations, the CCSTWS-OC study employed a triangular irregular network (TIN) model to 




develop a set of “synthetic” profiles for the survey years with data that were not coincident with the 

CCSTWS-OC transect locations (typically the pre-1992 surveys). For the purposes of the Bolsa Chica 

monitoring program, the same TIN model approach was used to “re-generate” the synthetic profiles 

used in the CCSTWS-OC. This approach was not necessary for the data that were coincident with the 

transect locations (1992-1997 and 2002). 

The LIDAR data consists of densely spaced topographic points derived from an airborne survey. 

These data encompass the entire shoreline of the Bolsa Chica study area, but do not extend below the 

waterline. Beach profiles were created at each of the five historical transects and the two newly 

established transects using a TIN model developed from the LIDAR results. 

Synthetic profiles also were developed for the two newly established transects for March 2002 and 

several of the pre-1992 CCSTWS-OC survey dates. Using the same TIN model approach described 

above, synthetic profiles were created for each case when historical survey data bracketed the location 

of the two newly established transects and at least one of the bracketing transects was not coincident 

with a historical transect. Profiles were generated for the following eight survey years: May 1963, 

July 1964, October 1966, April 1969, May 1973, April 1982, January 1983, and March 2002. 

Historical Beach Width Measurements 

U.S. Army Corps of Engineers personnel have acquired monthly beach width measurements along the 

Orange County coast since 1977. This extensive data set was initiated by Robert Clancy. Since the 

late 1980’s, Chuck Mesa of the Corps has continued the monthly data collection program. 

The data set contains measurements from a consistent back beach position to the break-in-slope at the 

beach berm. The location of the berm does not represent a vertically-referenced shoreline (such as the 

MSL shoreline). However, the measurements do provide an indication of gross changes in beach 

configuration. To differentiate these measurements from beach widths derived from profile data or 

from the beach width measurements collected on behalf of the Bolsa Chica project, they will be 

referred to hereafter as “Corps beach widths”. 

Three of the measurement stations are located within or immediately adjacent to the Bolsa Chica study 

area: 247+88, 308+88, and 424+44. These stations are not coincident with the transect locations used 

for the CCSTWS-OC or the Bolsa Chica monitoring program. The beach width measurements at these 

stations were retrieved from the U.S. Army Corps of Engineers (Mesa 2008b, 2009). 

Methodology 

Beach Profile Surveys 

Beach profile data were obtained on two occasions in 2008: May 12 and October 28. The methods 

employed were similar to those used on previous Orange County surveys. In consequence, the results 

are directly comparable. The data acquisition and reduction methods are described below. 

The wading and bathymetric portions of each survey were performed concurrently by two crews, as 

illustrated in Figure 2-10. Data were acquired along each transect from the back beach to a depth of 

approximately 14 m below NAVD88. Wave heights typically were less than 1 m during each of the 

surveys. 




The beach and surf zone were surveyed using a total station and a survey rodman. The total station 

was used to determine the position and elevation of the beach at each location occupied by the rodman. 

Each transect was surveyed from the back beach seaward through the surf zone until the survey rod no 

longer protruded above the water surface when held erect. This location, typically in a water depth of 

3.0 to 3.5 m below NAVD88, provided substantial overlap with the landward portion of the 

bathymetric survey. 

Bathymetric data were collected with a digital acoustic echo sounder operated from a shallow-draft 

inflatable survey vessel. A dynamic motion sensor, which provides real-time corrections to the echo 

sounder for wave-induced vessel heave, also was utilized. A GPS receiver was used to determine the 

position of each sounding. To improve the accuracy of each position, differential corrections 

transmitted in real-time from U.S. Coast Guard beacons were utilized (DGPS). All systems were 

interfaced to a laptop computer using the Hypack Max survey package. 

Figure 2-10. Beach profile survey operations 

The boat traveled along each transect from the offshore terminus to the surf zone guided by DGPS 

navigation. Soundings were acquired on a continuous basis (approximately 3 soundings per second), 

while positions were recorded at 1-second intervals. The DGPS position data and sounding data were 

merged using the Hypack software, with interpolated positions being assigned to the soundings 

acquired between position fixes. 

The calibration of the echo sounder was checked at periodic intervals during the survey using a 

standard “bar check” procedure. In addition, measurements of the speed of sound in sea water also 

were obtained at the offshore end of each transect using a recording conductivity, temperature, and 

depth (CTD) instrument. 




The data from the wading portion of each survey were processed using software developed by Trimble. 

The software read the raw total station data, and the coordinates and elevation of each data point were 

calculated and inserted into a CAD drawing. 

The raw data from the bathymetric portion of each survey consisted of Hypack files containing the 

position data and heave-compensated soundings. These data were edited for outliers using the Hypack 

Single-Beam Processing Module. The dynamic motion sensor utilized during the survey removed the 

majority of the wave contamination from the record in real time. To further minimize the influence of 

wave-induced vessel motion on several transects, however, a smooth line was faired through the echo 

sounder record prior to digitizing it with the Hypack software package. 

Corrections for the draft of the transducer and the measured speed of sound in sea water then were 

applied to the measured depths. The speed-of-sound profiles were confirmed using the results of the 

“bar check” calibration procedure. Finally, the corrected soundings were adjusted to NAVD88 datum 

using tide measurements made by the U.S. Department of Commerce, NOAA, at Los Angeles Harbor. 

To provide a more accurate representation of local tide conditions, the water levels recorded at Los 

Angeles Harbor were adjusted to the project site using the time and height differences published by 

NOAA (NOS, 2008). 

The adjusted soundings were thinned to a nominal horizontal interval of 3 m to produce a file size 

suitable for developing beach profile plots. The resulting x, y, z data (easting, northing, and elevation) 

were inserted into the CAD drawing containing the wading data. As indicated above, the fieldwork 

was conducted in such a manner as to provide substantial overlap between the wading and bathymetric 

portions of the survey. The processed data were examined in this region to insure that the two data sets 

were compatible. Once this confirmatory inspection had been completed, only the more detailed data 

in the region of overlap were retained (typically the bathymetric data). The less detailed data were 

purged, after which the wading and bathymetric data were merged to create a single digital file. 

Based on past experience, the vertical accuracy of the processed soundings is approximately ±15 cm. 

According to the Hemisphere GPS equipment specifications, the accuracy of horizontal positions 

obtained in the manner described above is less than 1.0 m. The electronic total station used to conduct 

the survey is capable of measuring ranges to within ±15 cm and elevation differences to within ±3 cm. 

Because the swimmer encountered waves and currents in the surf zone, however, the horizontal 

accuracy perpendicular to each transect (parallel to the shoreline) varied from minimal at short ranges 

to approximately ±5 m at the offshore end. 

Beach Width Measurement Program 

Monthly beach width measurements were acquired at each of the seven profile sites, commencing in 

January 2007 and continuing throughout 2008. 

The measurements were collected at tide heights ranging from -0.62 m to 1.96 m, NAVD. The beach 

width was recorded as the distance from a permanent point at the back beach to the approximate 

intersection of the still water line and the beach face. The foreshore slope also was measured and 

recorded along with the date and time of the observation. The measurements then were adjusted to 

approximate the MSL beach width using the foreshore slope and NOAA tide elevations. In addition, 

the distance from the back beach to the berm was measured. Although inherently less accurate than 




surveys, the method provides a cost-effective means to supplement the more accurate MSL beach 

widths derived from the semi-annual beach profile survey data. 

Results 

The beach profile plots are provided in Appendix 2-B. MSL beach widths and sediment volume data 

are presented in Appendices 2-C and 2-D, respectively. Appendix 2-E contains the beach width 

measurements obtained for the Bolsa Chica monitoring program, while Appendix 2-F contains those 

collected by the U.S. Army Corps of Engineers. 

Beach Profile Plots 

The 2008 beach profile data were used in conjunction with data from the historical surveys to create 

profile plots and compute changes in beach width and sediment volume. The beach profile plots 

developed from the survey data are provided in Appendix 2-B. The range on each profile plot 

represents the distance in meters seaward of the survey origin measured along the transect alignment. 

The elevation is given in meters relative to NAVD88. 

Two sets of beach profile plots were generated for each transect. The first set of plots shows all of the 

beach profile data available for each transect, while the second set of plots shows only those profiles 

obtained in during the three-year period encompassing the end of construction of the Bolsa Chica 

Lowlands Restoration Project and the first two years post-construction (October 2005 to October 

2008). The plots focusing on the recent three-year period also show the envelope of all available 

profile data that preceded the opening of the Bolsa Chica entrance channel in August 2006 (May 1963 

to March 2006). These plots also include two panels for each transect - one isolating the nearshore 

region of the profile and another displaying the entire profile length. 

Mean Sea Level Beach Widths 

Mean Sea Level (MSL) beach widths are provided in Appendix 2-C. The beach width was computed 

as the horizontal distance, in meters, between the landward edge of the beach sand and the point at 

which the beach profile intersected the plane of MSL Datum. In the Bolsa Chica area, MSL lies 0.79 

m above NAVD88. Notwithstanding the use of NAVD88 as the elevation reference for the profile 

data, MSL was adopted as the shoreline reference in the belief that it provides a more accurate 

indicator of changes in beach configuration. 

Sediment Volumes 

Sediment volume changes are provided in Appendix 2-D. The volume changes were computed along 

each transect for the entire width of the shorezone, and for that portion of the profile located above 

MSL (subaerial volume). 

The offshore boundary of the control volume for the beach above MSL was placed at the intersection 

of the profile and a horizontal line corresponding to the elevation of MSL. The offshore boundary for 

the shorezone was placed at the “statistical range of closure”. This parameter represents the distance 

seaward of the transect origin, beyond which profile variations are smaller than the accuracy of the 

survey technique. As implied by its definition, the statistical range of closure was adopted as the 

offshore boundary to separate the signal of true profile change from the noise of survey inaccuracy. 

The sea bottom elevation at the range of closure corresponds to the “depth of closure” or the depth at 

which sediment transport is not substantially affected by littoral processes. 

The statistical range of closure was determined for the five historical transects as part of the CCSTWS- 

OC. However, these boundaries were no longer appropriate due to the profile changes that resulted at 




several locations from the placement of the ebb bar offshore of the Bolsa Chica entrance. As a result, 

the statistical range of closure was re-computed for each historical transect and for the two new 

transects based on all available survey data collected between May 1963 and October 2007. The 

procedure used to calculate the statistical range of closure for each transect was identical to that 

employed for the CCSTWS-OC (USACE, 2002). The results are shown in Table 2-4. 

Statistical closure was assumed to occur at the point at which the standard deviation of all measured 

elevations ceased to decrease in value. The procedure used to compute the point of statistical closure 

at each profile is summarized below: 

Statistical closure was assumed to occur at the point at which the standard deviation of all measured 

elevations ceased to decrease in value. The procedure used to compute the point of statistical closure 

at each profile is summarized below: 

• Sea bottom elevations were interpolated at 15.2-m range intervals along all selected profiles. 

• The sample standard deviation of the interpolated elevations for all available survey profiles (σ) 

was calculated at each 15.2-m interval. 

• Statistical closure was assumed to occur at the point at which σ ceased to decrease. 

• The maximum depth of all available survey profiles at the point of statistical closure was 

recorded as the depth of statistical closure. 

• The distance from the transect origin to the point of statistical closure was recorded as the 

“range of statistical closure”. This range was adopted as the offshore boundary for the 

computation of shorezone volumes. 

Table 2-4. Statistical range and depth of closure at Bolsa Chica area transects. 

Transect Designation 

Range of Closure 

(m) 

Depth of Closure 

(m, NAVD88) 

249+30 473 -6.97 

311+22 900 -9.29 

318+30 793 -8.80 

333+30 717 -8.67 

350+71 519 -7.70 

378+29 381 -6.73 

423+89 549 -8.72 

The onshore boundary of the control volume for both the shorezone and subaerial volumes was placed 

at the landward edge of the beach sand. 

Beach Width Measurements 

The results of the beach width measurements obtained by Moffatt and Nichol at the seven Bolsa Chica 

area transects are presented graphically in Appendix 2-E. The plots include the MSL beach width and 

the horizontal distance from the back beach to the berm. 

The Corps beach widths, which consist of measurements from a consistent back beach position to the 

break-in-slope at the beach berm, are presented graphically in Appendix 2-F. 




Discussion 

The shoreline change assessment is based on the 45-year period between 1963 and 2008. Particular 

emphasis is placed on the three-year period encompassing the end of the construction of the Bolsa 

Chica Lowlands Restoration Project and the first two years post-restoration (October 2005 to October 

2008). This three-year period will be referred to as the “Bolsa Chica Monitoring Period”. The project 

components that influence coastal changes include placing approximately 929,326 m 3 (1,214,579 y 3 ) 

of sand in an ebb bar located offshore of the entrance channel during Winter 2005/2006, providing 

approximately 102,500 m 3 (133,962 y 3 ) of beach nourishment (50:50 north and south) to the shoreline 

adjacent to the channel in Summer 2006 and establishing tidal exchange at the entrance channel in 

August 2006. 

As indicated previously, the beaches along the Bolsa Chica study area has regularly benefited from the 

downdrift dispersal of the Surfside-Sunset nourishment material. A comprehensive account of the 

coastal changes in the area during the 34-year period between 1963 and 1997 can be found in the 

CCSTWS-OC (USACE, 2002). 

Profile Changes 

Long-Term Profile Changes (1963 to 2008): The above-water beach profiles obtained in 2008 are 

each near or seaward of the upper bound of the historical profile envelope at six of the seven Bolsa 

Chica area transects. The exception was Transect 378+29, located at Huntington Cliffs. These 

findings are consistent with the long-term trend of beach width and sediment volume gains identified 

in the CCSTWS-OC for the Bolsa Chica study area. Of the five historical transects, the accretion trend 

was absent only at Transect 378+29. 

Bolsa Chica Monitoring Period Changes (2005 to 2008): During the three-year Bolsa Chica 

Monitoring Period, above-water profile accretion occurred at the three transects located north of the 

entrance channel (249+30, 311+22, and 318+30). Modest gains also occurred at the southernmost 

transect (423+89). The greatest above-water volume gains occurred at Transect 311+22 and 318+30, 

located immediately north of the entrance channel. These gains may be explained by a combination of 

the beach nourishment placed in Summer 2006, onshore migration of the material placed in the ebb 

bar, and upcoast sediment trapping at the entrance jetties. Immediately south of the entrance channel 

at Transect 333+30, substantial above-water profile erosion occurred seaward of the berm. Volume 

gains are evident at this location landward of the berm, however, and are likely an artifact of the 2006 

beach nourishment. Further downcoast, the above-water beach at Transects 350+71 and 378+29 was 

characterized by modest erosion or stability. 

Offshore Ebb Bar: Approximately 1.5 million m 3 of sand was placed in an ebb bar located offshore of 

the Bolsa Chica entrance channel between November 2005 and May 2006. This bar is evident in the 

2007 and 2008 profiles at Transects 311+22, 318+30 and 333+30. Comparison of the 2007 and 2008 

profiles indicates the onshore migration of the ebb bar during the one-year period between the surveys. 

The most significant changes were isolated to depths above 8 m. 

Beach Width Changes 

2008 Beach Widths: Figure 2-11 shows the beach widths in the Bolsa Chica study area at the time of 

the May 2008 and October 2008 surveys. Each figure also includes the range of Fall and Spring beach 

widths for all available data between 1963 and 2002. At the time of the May 2008 survey, beach 

widths ranged from 21 m at Transect 378+29 to 109 m at Transect 423+89. The greatest beach width 




Figure 2-11. May 2008 and October 2008 beach widths 




at the time of the October 2008 survey was 107 m (Transect 423+89), while the narrowest beach width 

was 26 m (Transect 378+29). The beach width at Transect 318+30 (immediately north of the entrance 

channel) exceeded historical beach width envelope at the time of both the May and October 2008 

surveys. Further north at Transect 311+22, the May 2008 beach width exceeded the envelope, while 

the October 2008 beach width was within 2 m of the historical maximum. The beach width at Transect 

423+89 also exceed the envelope in May 2008. 

Long-Term Shoreline Changes (1963 to 2008): The time series plots in Appendix 2-C indicate a trend 

of long-term shoreline advance at six of the seven Bolsa Chica area transects during the 45-year period 

between 1963 and 2008. The exception was Transect 378+29, where beach widths were relatively 

stable during this period with no apparent trend. 

Figure 2-12 shows the net long-term beach width changes in the Bolsa Chica study area between May 

1963 and May 2008. To avoid a seasonal bias, the comparison utilizes the May 2008 survey rather 

than the more recent October 2008 survey. Shoreline advance predominated, with gains ranging from 

10 m at Transect 350+71 to 73 m at Transect 318+30. Shoreline retreat occurred at only one location, 

a loss of 12 m at Transect 378+29. 

Figure 2-12. Long-Term beach width changes, May 1963 to May 2008 




Bolsa Chica Monitoring Period Shoreline Changes (2005 to 2008): Beach width changes between 

October 2005 and October 2008 are shown in Figure 2-13. During the three-year period encompassing 

the construction of the Bolsa Chica Lowlands Restoration Project, the shoreline advanced at the three 

transects located north of the entrance channel (249+30, 311+22, and 318+30). The greatest gain, 24 

m, occurred at Transect 311+22. Shoreline retreat predominated at the survey sites located south of the 

entrance channel. Beach widths changes ranged from a gain of 1 m at Transect 333+30 to a loss of 14 

m at Transect 423+89. Similarly, investigation of the time series plots in Appendix 2-C indicates 

trends of shoreline advance north of the entrance channel and shoreline retreat south of the entrance 

channel during the Bolsa Chica Monitoring Period. 

Figure 2-13. Bolsa Chica monitoring period shoreline changes, October 2005 to October 2008 

Sediment Volume Changes 

Long-Term Subaerial Volume Changes (1963 to 2008): The long-term subaerial volume trends 

(Appendix 2-D) were similar to the long-term shoreline changes. Volume gains occurred at six of the 

seven Bolsa Chica area transects during the 45-year period between 1963 and 2008. In keeping with 

the shoreline change trends, the exception was Transect 378+29, where subaerial volumes were 

relatively stable during this period with no apparent trend. Figure 2-14, which shows the net longterm 

subaerial volume changes between May 1963 and May 2008, bears a striking resemblance to 

Figure 2-12 (showing shoreline changes for the same period). 




Figure 2-14. Long-Term subaerial volume changes, May 1963 to October 2008 

Bolsa Chica Monitoring Period Subaerial Volume Changes (2005 to 2008): Subaerial volume changes 

during the three-year Bolsa Chica Monitoring Period are shown in Figure 2-15. The subaerial volume 

changes were very similar to the beach width changes, with gains occurring north of the entrance 

channel and losses predominating south of the entrance channel. The primary discrepancy occurred at 

Transect 423+89, where the shoreline retreated but the subaerial volume increased. This apparent 

inconsistency can be explained by accretion of the beach between the waterline and the berm at the 

time of the October 2008 survey. 




Figure 2-15. Bolsa Chica monitoring period subaerial volume changes, Oct. 2005 to Oct. 2008 

Long-Term Shorezone Volume Changes (1963 to 2008): As described previously, the shorezone 

encompasses the entire littoral zone from the back beach to the depth of closure. Figure 2-16 shows 

the net long-term shorezone volume changes between May 1963 and October 2008 at each of the Bolsa 

Chica area transects. The comparison utilizes the May 1963 and October 2008 surveys because the 

shorezone volume is not subject to seasonal bias. Shorezone volume gains prevailed at each of the 

seven Bolsa Chica area transects. The gains ranged from 72 m 3 /m at Transect 378+29 to 1006 m 3 /m at 

Transect 318+30. 

The shorezone volume gains reflect not only the influence of the Surfside/Sunset nourishment 

activities, but also the ebb bar that was placed offshore of the entrance channel as part of the 

restoration project. The ebb bar, which was created by placing approximately 1 million m 3 of sand 

offshore, is evident in the 2007 and 2008 profiles at Transects 311+22, 318+30 and 333+30. The time 

series plot in Appendix 2-D show substantial volume gains at each of these transects between 2002 and 

2007. 




Figure 2-16. Long-Term shorezone volume changes, May 1963 to October 2008 

Bolsa Chica Monitoring Period Shorezone Volume Changes (2005 to 2008): It is not possible to 

quantify the shorezone volume changes for the Bolsa Chica Monitoring Period because the October 

2005 profile does not extend below the waterline. However, investigation of the time series plots in 

Appendix 2-D indicates that a trend of shorezone volume loss has prevailed at each transect between 

January 2007 and October 2008. This may be attributable dispersal of the ebb bar and natural 

shoreline erosion between Surfside-Sunset nourishment intervals. 

Beach Width Measurement 

Time series plots for the beach width measurements obtained at the seven Bolsa Chica area transects 

by Moffatt and Nichol and at three nearby locations by the U.S. Army Corps of Engineers are 

presented in Appendices 2-E and 2-F, respectively. 

The results of the beach width measurements obtained at the seven Bolsa Chica area transects are 

summarized in Table 2-5. During the two-year period between the January 2007 and December 2008 

observations, the MSL beach width decreased at three of the seven sites, increased at three locations, 

and was essentially unchanged (3 m or less) at the remaining site. In general, the shoreline tended to 

advance north of the entrance channel and retreat to the south. The greatest shoreline advance was 

14 m, and occurred north of the entrance channel at Transects 311+22 and 318+30. The greatest 

shoreline retreat, 22 m, occurred immediately south of the entrance channel at Transect 333+30, and at 

the north end of the study area at Transect 249+30. Shoreline change rates during the two-year period 

ranged from -10.9 m/yr at Transect 249+30 to 8.0 m/yr at Transect 318+30. 




Table 2-5. Beach width measurement program summary statistics, Jan. 2007 to Dec. 2008. 

Transect 

Range 

(m)) 

Distance to Berm (m) 

Ave 

(m) 

Change 

(m) 

Trend 

(m/yr) 

Range 

(m)) 

MSL Beach Width (m) 

Ave 

(m) 

Change 

(m) 

Trend 

(m/yr) 

249+30 57-86 67 -12 -11.7 73-104 85 -22 -10.9 

311+22 50-67 59 7 4.0 65-87 75 14 4.5 

318+30 56-77 65 9 6.7 69-99 82 14 8.0 

333+30 24-46 32 -22 -10.3 38-72 56 -22 -5.7 

350+71 22-37 28 -2 -5.9 34-53 47 -3 -2.7 

378+29 0-14 3 2 -2.8 6-33 18 6 -2.4 

423+89 78-99 85 -3 -0.2 95-110 102 -5 1.4 

The Bolsa Chica Monitoring Plan (USFWS, 2001b) defined beach nourishment triggers based on the 

monthly beach width observations at the Corps measurement sites within the study area. The 

minimum permitable beach width based on two consecutive monthly measurements was stipulated to 

be 15.2 m (50 ft). A second condition indicated that the 12-month rolling average beach width could 

not deviate from the long-term mean beach width (based on the period January 1980 to January 2000) 

by more than two standard deviations. Table 2-6 shows the beach width statistics for the three Corps 

measurement sites within the study that were provided in the monitoring plan. 

Table 2-6. Range and depth of closure at Bolsa Chica area transects. 

Station 

Berm Width (m) 

Range Mean Std. Deviation 

247+88 48 - 105 64.0 7.6 

307+88 12 - 59 33.2 7.3 

424+44 18 - 81 52.4 10.4 

Figures 2-17, 2-18, and 2-19 show the long-term rolling average berm width from October 2006 (preproject) 

to December 2008 at each of the three Corps measurement sites within the study area. The 

time series plots also show the minimum stipulated berm width (15.2 m), the long-term mean berm 

width, and a shaded area encompassing two standard deviations above and below the long-term mean 

berm width. 

The 12-month rolling average berm width remained above the minimum stipulated berm width 

(15.2 m) throughout the period at each of the sites. At 307+88 and 424+44, the 12-month rolling 

average berm width exceeded two standard deviations above the long-term mean. At no location, 

however, was the 12-month rolling average berm width less than two standard deviations below the 

long-term mean. 




120 

12-Month Rolling Average Berm Width (m) 

100 

80 

60 

40 

20 

long-term mean = 64.0 m 

minumum permitable beach width 

+-2 Standard Deviations 

from Long-Term Mean 

0 

2005 2006 2007 2008 2009 2010 

Year 

Figure 2-17. Twelve -Month average berm width at Corps Station 247+88 

120 


100 

80 

60 

40 

20 





0 

2005 2006 2007 2008 2009 2010 

Year 

Figure 2-18. Twelve -Month average berm width at Corps Station 307+88 




120 


100 

80 

60 

40 

20 





0 

2005 2006 2007 2008 2009 2010 

Year 

Figure 2-19. Twelve-Month average berm width at Corps Station 424+44 

Influence of Entrance Channel 

Shoreline Changes Adjacent to Entrance Channel: Between October 2005 and October 2008, the 

beaches upcoast (north) of the new entrance channel accreted, while those downcoast (south) of the 

channel tended to erode (Figure 2-13). Figure 2-20 compares the shoreline changes immediately north 

of the channel (Transect 318+30) with the changes for the remaining upcoast monitoring sites 

(Transects 249+30 and 311+12). The shoreline at the three upcoast transects responded similarly 

between October 2005 and January 2007. Following the opening of the new channel (January 2007 to 

October 2007), the shoreline at Transect 318+30 retreated slightly, while the beaches at the other 

upcoast sites advanced. Between October 2007 and October 2008, the shoreline advanced at Transect 

318+30, stabilized at Transect 311+12, and retreated at Transect 249+30. 

A time series of the shoreline changes at the four transects located downcoast (south) of the entrance 

channel is shown in Figure 2-21. The shoreline changes at Transect 333+30 (immediately downdrift of 

the channel) were nearly identical to those at Transects 350+71 and 423+89, and indicate a trend of 

shoreline retreat between October 2005 and October 2007. The shoreline changes at Transect 378+29 

differed only modestly. During the most recent one-year period (October 2007 to October 2008), 

modest shoreline advance occurred at the two transects nearest the entrance channel (333+30 and 

350+71). In contrast, the shoreline retreated at the remaining sites. 

Volume Changes Adjacent to Entrance Channel: The subaerial volume changes upcoast of the 

entrance channel (Figure 2-22) responded similarly to the shoreline changes. The subaerial volume 

increased during the three-year period at each of the sites, with the most pronounced gains occurring at 

Transects 311+22 and 318+30. 




Figure 2-20. Shoreline changes at upcoast transects, October 2005 to October 2008 

Figure 2-21. Shoreline changes at downdrift transects, October 2005 to October 2008 




Figure 2-22. Subaerial volume changes at upcoast transects, October 2005 to October 2008 

Figure 2-23. Subaerial volume changes at downcoast transects, October 2005 to October 2008 




As shown in Figure 2-23, subaerial volume losses prevailed after January 2007 at the two downcoast 

transects nearest the entrance channel (333+30 and 350+71). Because this period followed the opening 

of the entrance channel, particular vigilance is warranted at this site during future monitoring activities. 

The remaining downcoast sites were relatively stable during this period. (Note: It is not possible to 

assess the shorezone volume changes for the Bolsa Chica Monitoring period because the October 2005 

profile does not extend below the waterline). 

Sediment Trapping in the Full Tidal Basin: As indicated in Section 2.1, approximately 158,000 m 3 of 

sediment was deposited in the lagoon during the 17-month period between August 2006 and January 

2008. Sedimentation was reduced substantially during the second year (11-month period between 

January 2008 to December 2008) to approximately 46,000 m 3 . While a small fraction of this material 

may have resulted from redistribution of basin sediments or aeolian processes, nearly all of the 

sediment has entered the basin from the ocean. It is possible that the high shoaling rate during the first 

year was a transient effect attributable to inlet stabilization, and increased propensity for sedimentation 

due to the proximately of the pre-filled ebb bar and widened beaches adjacent to the inlet. The reduced 

shoaling rate during the second year is likely attributable to a reduced tidal prism due to infilling of the 

FTB and the stabilization of the aforementioned local sediment sources (nourished beaches and ebb 

bar). 

The shoaling rate measured during the initial 17-month period was on the same order of magnitude as 

the alongshore sediment transport rates developed as part of the CCSTWS-OC sediment budgets 

(estimated to range from 108,000 m 3 /y to 125,000 m 3 /y). As a result, particular attention is warranted 

in monitoring the flood shoal accumulation rates following the maintenance dredging in early 2009 to 

understand if the initial sedimentation was transitory or should be expected following future dredging 

episodes. 

In the event that trapping rates detected during the initial post-opening are not transitory, these rates 

are of a significant magnitude to be of major concern to longshore transport in the littoral cell. If left 

unchecked and unmanaged, the primary implication of a substantial reduction of the longshore 

sediment supply is shoreline erosion downdrift of the entrance channel. The Bolsa Chica project, 

however, incorporates two sand management measures to actively address the potential for downdrift 

erosion by eliminating or substantially reducing the net long-term loss of sand downcoast. To 

compensate for anticipated short-term sediment losses from the littoral budget due to the natural 

formation of an ebb bar, initial lagoon shoaling, and fillet formation along the jetties, the ebb bar 

located offshore of the entrance channel was pre-filled, and supplemental sand was placed as beach 

nourishment adjacent to the channel at the time of construction. These pre-fills were intended to 

minimize littoral sand loss to ebb bar formation and provide supplemental sand for early inlet 

stabilization. In addition, the long-term project sediment management plan provides for periodic 

down-coast beach nourishment using sediment derived from the FTB during maintenance dredging 

operations. This bypassing operation essentially restores the sediment lost from the littoral budget to 

the downdrift beaches over the long-term. Taken together, these measures are anticipated to maintain 

the historical supply of sediment to the beaches located south of the entrance channel. The first such 

maintenance dredging will be conducted in early 2009. 




III. MAINTENANCE DREDGING PROGRAM 

The maintenance dredging program is planned as a sand management action to maintain “no net loss” 

of sand to the downcoast beaches as required in the EIR/EIS and project permits, as well as to ensure 

the vitality of the tidal system. During regular maintenance dredging operations, sand will be removed 

from the flood shoal of the FTB within the original dredging footprint, in a region that can extend from 

the tidal inlet north to approximately the position of the Freeman Creek culvert. The final area may be 

slightly larger or smaller depending on shoaling patterns determined from pre-dredge surveys. Sand 

dredged from the basin will be placed at the beach or nearshore areas based on the results of beach 

monitoring as well as a consideration of the volume of material to be dredged. 

Preliminary engineering studies (M&N 1999) and the Basis of Design Report (M&N 2003) estimated 

the quantity of sand that would accrete in the lagoon would be on the order of 126,000 m 3 (165,000 

yd 3 ) during the first year, 102,000 m 3 (134,000 yd 3 ) during the second year, 49,000 m 3 (64,000 yd 3 ) 

during the third year, and 7,600 m 3 (10,000 yd 3 ) during the fourth year post opening. The reduced 

sand influx rate in later years was predicted as a result of anticipated system muting. Therefore, the 

need for maintenance dredging would arise before later low influx rates would be realized. 

Maintenance dredging plans included provisions for dredging deeper than the original dredge depth but 

within originally permitted dredge depths. This could add as much as 400,000 m 3 (550,000 yd 3 ) of 

dredging to maintenance sand removals from the FTB. This additional advance maintenance quantity 

would provide a longer interval between dredging cycles if it were implemented. 

3.1 DREDGING TRIGGERS 

The following parameters were monitored and analyzed to evaluate the functioning of the system and 

determine when dredging should be performed. Some of these parameters have previously established 

dredging triggers associated with them, as indicated, while others have thresholds that were established 

by the monitoring team, based on the need to sustain the biological and hydrological functioning of the 

system. 

Tidal Muting 

Muting of the average low tide elevations (Mean Low Water) on the order of 0.5 feet would 

indicate that the flood shoal maintenance dredging was warranted (Biological Monitoring and 

Follow-up Plan [USFWS 2001]). 

Muted Tidal Basin Function 

The flood shoal should be dredged if the tidal drainage in the MTBs is impeded and the MTB 

function is degraded as a result of inefficient drainage. Tidal monitoring in the FTB will help 

determine the dredging trigger related to tidal drainage in the MTBs (Monitoring Team 

determination). 

Beach Width 

Flood shoal dredging should occur if any beach is found to be narrower than 50 feet, based on two 

consecutive monthly beach width measurements, and/or if any 12-month rolling average of beach 

widths which deviate more than 2 standard deviations from the mean beach width, using the 20- 

year historic record to establish these means and standard deviations (Beach Monitoring Plan 

[USFWS, 2001]). 




Loss of Subtidal Habitat 

The flood shoal should be dredged if a 10% decrease in habitat acreage occurs (Basis of Design 

Report [M&N, 2003]). 

Closure Risk 

The flood shoal should be dredged if it is determined that the inlet is at risk of closure in a single 

storm scenario due to the localized shoaling pattern (Monitoring Team determination). 

Water quality 

Tidal circulation in the FTB will be slightly less efficient under the muted tidal condition. 

However, the FTB should still have an excellent circulation condition with a residence time of a 

few days. The water quality will degrade if the inlet is closed. At present, the large size of the 

FTB and the significant wave fetch is believed to be adequate to sustain good water quality even in 

highly muted conditions. However, substantial deviations in water quality parameters that suggest 

isolation from strong oceanic influences should trigger dredging of the flood shoal (Monitoring 

Team determination). 

3.2 TRIGGER ANALYSIS 

Analysis of Tidal Muting Trigger 

A review of the tidal ranges in the FTB and LAOH indicates that the differences in the high tide 

elevations between the two sites are very small. This implies that the overall measurement is reliable 

and there was no muting of the high tides in 2008. The low tides were muted in 2008 and the degree 

of muting was a result of flood shoal accretion in the basin. While the original tidal muting trigger 

within the Biological Monitoring and Follow-up Plan (USFWS 2001) was based on muting of the 

average low tide elevations (Mean Low Water) on the order of 0.5 feet, this trigger is too high to avoid 

adverse effects on tidal circulation and drain-out conditions from the MTBs. As a result, a different 

trigger based on lower tide levels is appropriate. 

Several factors are important to consider in setting tidal muting or tidal drainage triggers for 

maintenance dredging events. Tidal muting is positively correlated with tidal range, with greater 

muting occurring during spring tides and less muting occurring during neap tides. The trend of tidal 

muting is for gradually increased muting over time, with greater punctuated increases and reductions in 

muting that are likely coincident with significant changes in littoral transport and flow patterns across 

the flood shoal (this occurred during the winter of 2007-08, Figures 2-5B and 2-6). The amount of 

muting shown in Table 2-2 increased over time as the flood shoal expanded in the FTB. 

Tidal plots in the Appendix 2-A and the low tide muting in Table 2-2 show an average spring low tide 

muting of 0.29 m from oceanic conditions over 2007 (January through December). For that same 

monitoring period in 2008, the spring low tide muting averaged 0.54 m. However, high water level 

management issues in the west MTB, necessitating gate closures and self-regulating tide gate 

adjustments to reduce tidal range, extended from approximately May 2008 through the remainder of 

the year. During this period, the average low spring tide was muted 0.62 m from oceanic conditions. 

For the preceding few months during which the west MTB was open, the muting level was 0.39 m and 

constraints were minimal. 




While tidal muting from oceanic conditions provides a good means by which drainage loss may be 

measured, it is more difficult and less direct than establishing a maintenance trigger that can be readily 

measured from recording instrumentation. Further, during periods of sea surface rise, such as during 

an El Nino Southern Oscillation (ENSO) event, it may be expected that there will be less difference 

between the oceanic low tides and those within the FTB, yet MTB and Freeman Creek drainage 

conditions will be even more severely affected than under normal shoal-driven muting. For this 

reason, it is worth considering the use of the lowest achieved tides within the FTB as a metric for 

maintenance dredging action. 

During periods when the average of the lowest spring tides in each tide series achieved elevations at or 

below –0.05 m NAVD, the west MTB functioned well. When the average of the lowest spring tides in 

each tide series achieved elevations at or above 0.28 m NAVD, the function of the west MTB was 

impaired and operational ranges were necessarily curtailed to avoid flooding above designed 

operational levels. As an interim-operating trigger for maintenance dredging, it is recommended that 

the occurrence of four or more consecutive low spring tides in the FTB that fail to achieve low 

elevations of 0.12 m NAVD or lower, on a running average basis, should suggest dredging is likely 

necessary. It is anticipated that maintenance triggers will need to be further modified in the future as 

the central and east MTBs are opened to tidal flows. In addition, once the Freeman Creek gate is open 

to the FTB it will be important to assess the influence of FTB elevations on operational drainage from 

this basin as well. It is important to note that both the central and east MTBs have a lower designed 

operational elevation than does the west MTB. As a result, it is anticipated that maintaining limited 

muting within the FTB will be even more important to the intended operation of these basins than to 

the higher elevation west MTB. 



ranging from 2.02 to -0.27 m NAVD. 

• Remove the dredge trigger of Mean Low Tide muting of 0.15 m. 


spring tide series exceeding 0.12 m NAVD, as described above. 




• Remove the flood shoal in winter 2008/2009 as scheduled to reduce the tidal muting effects. 

Recommendations relating to this dredging trigger are currently considered preliminary in nature as the 

muting of the system affects the functioning of the MTBs, which have yet to be fully opened. As a 

result, final dredging triggers relating to tidal muting should only be set after opportunities exist to 

monitor the full performance of all of the MTBs under normal and muted conditions. 

Analysis of Beach Width Trigger 

The Bolsa Chica Monitoring Plan defined beach nourishment triggers based on the monthly beach 

width observations at the USACE measurement sites within the study area. The minimum permittable 




beach width based on two consecutive monthly measurements was stipulated to be 15.2 m. A second 

condition indicated that the 12-month rolling average beach width could not deviate from the longterm 

mean beach width (based on the period January 1980 to January 2000) by more than two standard 

deviations. The presumption is that the deviation from beach width must also be towards a declining 

width from the benchmark period. 

Figures 2-17, 2-18, and 2-19 show the long-term rolling average berm width from October 2006 (preproject) 

to December 2008 at each of the three USACE measurement sites within the study area. The 

time series plots of the monitoring data also show the minimum stipulated berm width (15.2 m) (red), 

the long-term mean berm width (green), and a red shaded area encompassing two standard deviations 

above and below the long-term mean berm width. 

The 12-month rolling average berm width remained well above the minimum stipulated berm width 

(15.2 m) throughout the period at each of the sites. At 307+88 and 424+44, the 12-month rolling 

average berm width exceeded two standard deviations above the long-term mean. The 12-month 

rolling average berm width was never less than two standard deviations below the long-term mean 

during 2007. Given the beach width criteria, it is not expected that beach erosion will trigger the need 

for maintenance dredging and replenishment as long as the Surfside-Sunset nourishment program 

continues, as this upcoast feed of littoral sand has been building beach width over time. 

At the present time, the beach response triggers established for the project maintenance dredging 

requirements are not particularly responsive to the relatively low volume of sand lost to entrainment 

and flood shoal capture. However, the project does not appear to be resulting in substantive broad 

scale changes in beach conditions beyond a localized influence of the jetties on beach form in the 

immediate vicinity of the inlet. As this maintenance trigger was developed to ensure protection of 

littoral beach conditions and it appears that these are being protected, no recommendation for a trigger 

change is made at this time. It would, however, be appropriate to consider reduction or even future 

elimination of the beach monitoring program given the highly unlikely condition that any of these 

maintenance triggers will be tripped prior to the requirements to perform maintenance dredging for 

tidal muting corrections. 

Analysis of Subtidal Habitat Trigger 

The flood shoal volume, the area of shoaling, and shoaling rate all have occurred similarly to processes 

predicted during the project design. Maintenance dredging should occur as recommended in the 

design as well. A recommended maintenance dredge trigger is the reduction of intertidal habitat area. 

The Basis of Design Report (M&N 2003) indicates that dredging should occur when habitat reduction 

reaches 10%. However, this criterion is probably too restrictive and should be reconsidered. Previous 

analyses as part of preliminary engineering studies show a rapid loss of 10% habitat within 1.3 years, 

and a subsequent habitat loss reaching 24% after 2 years (M&N 1999) at the predicted shoaling rate. 

The actual application of this trigger is confounded by the low frequency (not more than once a year 

and planned for lower frequency in the future) habitat mapping and bathymetric assessments, which 

are needed to assess intertidal habitat losses. As a result of these complications the maintenance 

dredging program should consider eliminating this trigger as the system matures and the intensity of 

biological and physical monitoring are diminished over time. In the interim period, while adequate 

data are being collected to complete these assessments (over the next 3-7 years) a two-year 

maintenance dredging frequency would be appropriate considering measured versus predicted shoaling 

volumes, tidal muting, and habitat loss. A revised dredge trigger based on habitat loss should be: when 




24% of low intertidal habitat converts to subtidal habitat or when 24% of the subtidal basin is lost to 

intertidal flood shoaling near the ocean inlet, dredging is warranted. In either condition, the habitat 

functionality would be considered to be impaired from the initial design objectives. 

Analysis of Closure Risk Trigger 

The closure risk trigger is not specifically defined or quantified, but is presented as an opinion of risk 

due to the shoaling pattern of the inlet. A review of the bathymetric changes at the inlet shows that the 

major cross-sectional flow area varies by season and is presently located within a very narrow thalweg 

on the southern side of the inlet (Figure 2-2). Based on the quantity of material passing through the 

inlet and the significant narrowing of the thalweg, it is prudent to recommend dredging as needed to 

prevent a catastrophic closure of the inlet in a large storm event. 

Of greatest concern relative to an episodic closure event are large accumulations of sand within the 

inlet channel, high and over-steepened channel banks, and the sinuous course of flow between high 

sand bars and adjacent to the armored shoreline. In such cases as these, a major storm event, or series 

of events, combined with a weak neap tide series could lead to either full or partial closure of the 

mouth. This could then result in loss of drainage and rising water levels within the MTBs and 

Freeman Creek. 

As conditions necessary to cause a catastrophic closure event have not yet materialized, however, 

response to such an occurrence should be included in emergency planning contingencies. In the event 

such a closure occurred, it is likely that tidal flows could be restored to pre-event conditions by 

excavation of the channel during a strong ebbing tide. 

Analysis of Water Quality Trigger 

This trigger for maintenance dredging would be met if the water quality within the FTB were to begin 

to exhibit conditions of impaired circulation resulting in degradation of field measurable parameters of 

dissolved oxygen, considerably rising temperatures during summer months, or high resident plankton 

blooms that were not reflected in the open coastal waters. At the present time, the FTB waters exhibit 

conditions comparable to those of the open coast with oceanic variability strongly driving conditions in 

the areas of the FTB located closest to the inlet and only moderate variance from ocean conditions 

further into the basin. The FTB closely matched the ocean temperature in the winter, with slightly 

higher temperatures than the ocean in the summer months, a condition typically seen in other coastal 

embayments in the region. Dissolved oxygen levels measured at Bolsa Chica were within the expected 

range and reflected the strong influence of diurnal tidal flow, and were generally above healthy levels 

of 5.5 mg/L, with daily tidal peaks in the 7.5 to 8.5 mg/L range. There were no significant local 

plankton blooms during either 2007 or 2008. Based on these conditions, water quality triggers for 

maintenance dredging were not tripped during the 2008 monitoring period. 

3.3 DREDGE TRIGGERS - CONCLUSIONS AND RECOMMENDATIONS 

In reviewing the established dredging triggers, it is clear that some of the triggers may never be met 

except under extreme circumstances, while more significant triggers may exist that have not as yet 

been quantified. Chronic beach erosion triggers are not likely to be met because of the ongoing 

replenishment at Surfside-Sunset and its effect on long-term beach growth trends. Similarly, acute 

erosion triggers are not likely to be met due to the generally broad beach profiles at trigger point 

transects. This is not to say that beaches would not benefit from replenishment with flood shoal sand 




bypass. Rather, it acknowledges that beach erosion is not likely to occur to the extent that would 

trigger an obligatory maintenance dredging event for replenishment purposes. 

It is more likely that maintenance dredging will be required to address an intrinsic system need related 

to the functionality of the MTB tidal control structures. Final triggers to address this issue will need to 

be set once all of the MTBs are open to the FTB and have operated under both normal and muted FTB 

conditions. 



ranging from 2.02 m to -0.27 m NAVD. 

• Remove the dredge trigger of the Mean Low Tide muting of 0.152 m. 


spring tide series exceeding 0.12 m NAVD, as described above. 




• Continue the tidal monitoring program to show effects of the first maintenance dredging event and 

to assess the relationship between flood shoaling and tidal muting. 

• Remove the flood shoal in winter 2008/2009 as scheduled since effects of the flood shoal impede 

the tidal ebbing from the entire site. 

• The beach width dredging trigger should be modified to reflect a more current set of beach width 

data that includes the effects of the 2002 Surfside-Sunset nourishment. In addition, the trigger 

should indicate that dredging should be performed when the beach width is less than two standard 

deviations from the mean beach width, since being greater than two standard deviations does not 

indicate a need for dredging. 

• Consider phasing out the beach width triggers, as these are not likely to ever be tripped prior to 

maintenance dredging triggers that address muting and impairment of the MTBs. 

• Continue bathymetric monitoring, and anticipate another maintenance dredging event in two years. 

3.4 MAINTENANCE DREDGING PLAN 

The first maintenance-dredging event occurred in early 2009 based on shoal sediment accumulation 

during the first two years post-opening. Since this dredging occurred outside of the present report 

window, the details of the dredging program and recommendations for modification of dredging in the 

future are to be discussed in the 2009 report. However, it is prudent to make two recommendations at 

the present time as they are highly pertinent to maintenance actions and trigger setting. 




First, consideration should be given to dredging to the permitted depth of the final engineering design 

depths to extend the period between maintenance events. Dredging at the time of initial construction 

was not completed to full design depths within the maintenance basin. If deepening of the 

maintenance basin were completed, this would garner additional time between dredging events and 

would improve dredging efficiency by capturing a greater volume of sediment in a more localized and 

recoverable area nearer the inlet. 

Second, the pre-dredging contracting process can consume a considerable period of time and thus work 

should be completed to streamline and pre-prepare to the maximum extent practical prior to 

maintenance triggers being tripped. This would allow for a reduced period over which the system 

functions in an impaired condition prior to completing maintenance dredging. To accomplish this 

would require: preparation of the majority of the plans and specifications, completion of permitting 

based on a maintenance basin plan and dredge volume range, preparation of bid and contract 

documents, and obtaining maximum flexibility for the dredging window of work. 




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Nelson, J.S., E.J. Crossman, H. Espinosa-Pérez, L.T. Findley, C.R. Gilbert, R.N. Lea, and J.D. 

Williams. 2004. Common and Scientific Names of Fishes from the United States, Canada, and 

Mexico. Sixth Edition. American Fisheries Society, Special Publication 29, Bethesda, 

Maryland. 386 pp. 

Powell, A. N. and C. L. Collier. 1998. Reproductive Success of Belding’s Savannah Sparrows in a 

Highly Fragmented Landscape. The Auk 115(2): 508-513. 

Ricketts E.F., J. Calvin, J.W. Hedgpeth. 1968. Between Pacific Tides. Stanford University Press, 

California, 614 pp. 

Thrush, S.F., R.B. Whitlatch, R.D. Pridemore, J.E. Hewitt, V.J. Cummings, and M.R. Wilkinson. 

1996. Scale-dependent recolonization: The role of sediment stability in a dynamic sandflat 

habitat. Ecology 77(8):2472-2487. 

U.S. Army Corps of Engineers (USACE). 2002. Coast of California Storm and Tidal Wave Study - 

South Coast Region - Orange County, USACE, Los Angeles District, 545 pp + appendices. 




U.S. Fish and Wildlife Service. 2001a. Bolsa Chica Lowland Restoration Project Biological 

Monitoring and Follow-up Plan. 

U.S. Fish and Wildlife Service. 2001b. Bolsa Chica Lowland Restoration Project Beach Monitoring 

Plan. 

Zembal, R., J. Konecny, and S. M. Hoffman. 2006. A survey of the Belding’s Savannah sparrow 

(Passerculus sandwichensis beldingi) in California, 2006. Calif. Dep. Fish and Game, Habitat 

Conservation Planning Branch, Species Conservation and Recovery Program Report 2006-03, 

Sacramento, CA. 15pp. 




APPENDIX 1-A. YEAR 1 FIELD SURVEY DATES 




2008 field survey dates. 

WATER QUALITY MONITORING 

January 08 Monitoring Quarter Deployed Jan 10, 2008 Two units deployed for 30 days 

April 08 Monitoring Quarter Deployed April 2, 2008 Two units deployed for 30 days 

July 08 Monitoring Quarter Deployed July 1, 2008 Two units deployed for 30 days 

SOILS MONITORING 

Year 2 Monitoring Sept 30 to Oct 2, 2008 Samples collected 

VEGETATION MONITORING 

Year 2 Monitoring May 13, 2008 Aerial imagery collected 

Year 2 Monitoring September 17, 2008 Vegetation map ground-truthing 

Year 2 Monitoring August 14 and 21, 2008 Transect monitoring 

Year 2 Monitoring August 14 and 21, 2008 Eelgrass sonar survey 

Year 2 Monitoring August 20 & 21, 2008 Cordgrass monitoring 

FISHERIES MONITORING 

January ’08 Monitoring Quarter January 17 & 24, 2008 Fisheries sampling 

April ’08 Monitoring Quarter April 2 & 7, 2008 Fisheries sampling 

July ’08 Monitoring Quarter July 7 & 17, 2008 Fisheries sampling 

October ’08 Monitoring Quarter October 15 & 27, 2008 Fisheries sampling 

AVIAN MONITORING 

2008 Sensitive Species Nesting Season March to Sept, 2008 SNPL and LETE monitoring 

2008 Nesting Season April 21 & 22, 2008 1 st Belding’s Sav. Spar. Survey 

2008 Nesting Season May 12 & 13, 2008 2 nd Belding’s Sav. Spar. Survey 

February ’08 General Bird Survey February 14 & 15, 2008 Full survey of site for all species 

April ’08 General Bird Survey April 10 and 11, 2008 Full survey of site for all species 

June ’08 General Bird Survey June 25 & 26, 2008 Full survey of site for all species 

August ’08 General Bird Survey August 19 & 20, 2008 Full survey of site for all species 

October’08 General Bird Survey October 1 & 2, 2008 Full survey of site for all species 

December ’08 General Bird Survey December 18 & 19, 2008 Full survey of site for all species 

INLET BATHYMETRIC MONITORING 

Winter 2007/2008 Survey January 10, 2008 Bathymetric survey of inlet 

Summer 2008 Survey July 1, 2008 Bathymetric survey of inlet 

Winter 2008/2009 Survey Dec 23, 2008/Jan 28, 09 Bathymetric survey of inlet 

TIDAL MONITORING 

2008 Monitoring Jan 1 to Dec 31, 2008 Continuous logging in FTB 

BEACH MONITORING 

January 2008 Beach Width Survey January 18, 2008 7 Sites Measured 




February 2008 Beach Width Survey February 21, 2008 7 Sites Measured 

March 2008 Beach Width Survey March 21, 2008 7 Sites Measured 

April 2008 Beach Width Survey April 21, 2008 7 Sites Measured 

May 2008 Beach Width Survey May 22, 2008 7 Sites Measured 

June 2008 Beach Width Survey June 20, 2008 7 Sites Measured 

July 2008 Beach Width Survey July 21, 2008 7 Sites Measured 

August 2008 Beach Width Survey August 22, 2008 7 Sites Measured 

September 2008 Beach Width Survey September 20, 2008 7 Sites Measured 

October 2008 Beach Width Survey October 24, 2008 7 Sites Measured 

November 2008 Beach Width Survey November 18, 2008 7 Sites Measured 

December 2008 Beach Width Survey December 19, 2008 7 Sites Measured 

Spring 2008 Beach Profile Survey May 12, 2008 Profile Survey - 7 Transects 

Fall 2008 Beach Profile Survey October 28, 2008 Profile Survey - 7 Transects 




APPENDIX 1-B. SAMPLING LOCATION COORDINATES 




Sampling Location Coordinates 

California State Plane, Zone 6, NAD 83, Meters 

Field Element Station and Replicate ID X Y 

Vegetation RI 1 stop 1,833,325.64 671,485.78 

Transects RI 1 start 1,833,366.34 671,514.44 

RI 2 stop 1,833,431.95 671,673.61 

RI 2 start 1,833,464.57 671,635.45 

RI 3 stop 1,833,526.47 671,445.14 

RI 3 start 1,833,498.34 671,403.74 

FTBW 1 stop 1,834,331.54 671,268.08 

FTBW 1 start 1,834,365.01 671,305.46 

FTBW 2 stop 1,834,143.34 671,411.92 

FTBW 2 start 1,834,178.67 671,448.99 

FTBW 3 stop 1,833,979.61 671,626.83 

FTBW 3 start 1,834,015.89 671,661.42 

FTB north stop 1,833,816.71 671,931.03 

FTB north start 1,833,845.78 671,970.35 

EMTB 1 stop 1,834,502.81 671,355.14 

EMTB 1 start 1,834,552.68 671,353.17 

EMTB 2 start 1,834,623.34 671,566.11 

EMTB 2 stop 1,834,614.84 671,614.77 

EMTB 3 stop 1,834,881.73 671,512.94 

EMTB 3 start 1,834,899.29 671,465.86 

CMTB 1 stop 1,834,387.15 671,693.14 

CMTB 1 start 1,834,416.09 671,652.24 

CMTB 2 stop 1,834,046.59 671,740.55 

CMTB 2 start 1,834,046.26 671,690.73 

CMTB 3 stop 1,834,194.00 671,620.91 

CMTB 3 start 1,834,167.97 671,578.10 

WMTB 1 start 1,834,129.94 671,948.04 

WMTB 1 stop 1,834,084.83 671,926.02 

WMTB 2 stop 1,834,179.65 672,099.48 

WMTB 2 start 1,834,219.58 672,070.02 

WMTB 3 start 1,833,962.40 671,993.38 

WMTB 3 stop 1,833,912.52 671,996.52 

MPM1 start 1,833,285.22 671,920.30 

MPM1 stop 1,833,235.92 671,925.71 

MPM2 start 1,833,368.76 671,974.94 

MPM 2 stop 1,833,318.94 671,976.42 

MPM3 start 1,833,423.99 672,050.83 

MPM3 stop 1,833,440.42 672,003.96 




Purse Seine Station 1 Rep 1 1,833,662.56 671,875.62 

Station 1 Rep 2 1,833,897.57 671,479.91 

Station 1 Rep 3 1,834,106.99 671,308.46 

Station 2 Rep 1 1,834,554.56 670,690.03 

Station 2 Rep 2 1,834,463.66 670,337.65 

Station 2 Rep 3 1,834,366.47 670,039.54 

Otter Trawl Station 1 Rep 1N 1,833,739.41 671,870.60 

Station 1 Rep 1S 1,833,832.46 671,638.59 

Station 1 Rep 2N 1,833,728.03 671,609.96 

Station 1 Rep 2S 1,833,843.77 671,388.44 

Station 1 Rep 3N 1,833,962.78 671,461.67 

Station 1 Rep 3S 1,834,012.69 671,215.96 

Station 2 Rep 1N 1,834,448.76 670,736.71 

Station 2 Rep 1S 1,834,420.89 670,489.02 

Station 2 Rep 2N 1,834,523.64 670,509.52 

Station 2 Rep 2S 1,834,571.90 670,263.45 

Station 2 Rep 3N 1,834,452.21 670,173.52 

Station 2 Rep 3S 1,834,463.48 669,923.39 

Large Beach Pocket Marsh Rep 1 1,833,710.06 672,144.96 

Seine Pocket Marsh Rep 2 1,833,470.21 672,021.93 

Pocket Marsh Rep 3 1,833,273.77 671,924.75 

Station 1 Rep 1 1,833,797.81 671,938.86 

Station 1 Rep 2 1,833,686.35 671,401.07 

Station 1 Rep 3 1,834,157.35 671,362.85 

Station 2 Rep 1 1,834,680.13 670,539.00 

Station 2 Rep 2 1,834,317.83 670,047.05 

Station 2 Rep 3 1,834,685.46 670,314.34 

Benthic Station 1 Rep 1 1,833,780.44 671,943.61 

Station 1 Rep 2 1,833,624.94 671,941.40 

Station 1 Rep 3 1,834,130.42 671,378.73 

Station 2 Rep 1 1,834,676.95 670,541.17 

Station 2 Rep 2 1,834,688.47 670,299.59 

Station 2 Rep 3 1,834,332.74 670,053.99 

Station 3 Rep 1 1,833,593.88 671,759.67 

Station 3 Rep 2 1,833,700.39 671,385.09 

Station 3 Rep 3 1,833,851.86 671,284.76 

Water Quality Station 1 1,833,687.14 671,735.95 

Station 2 1,834,520.64 670,639.78 




APPENDIX 1-C. CORDGRASS MONITORING PHOTOS 



Cordgrass Site 1. Looking south to north. 

Mean shoot density: 66 shoots/m 2 ; mean canopy height: 20 cm 

Cordgrass Site 2. Looking west to east. 




Cordgrass Site 4. Looking west to east.. 







No cordgrass detected. 



Cordgrass Site 8. Looking east to west.. 




Cordgrass Site 9. Looking east to west. 


Cordgrass Site 10. Looking east to west. 


Cordgrass Site 11 Looking east to west. 

No cordgrass detected. 

Cordgrass Site 14. Looking south to north. Single plant. 

Shoot density: 15 shoots/m 2 ; canopy height: 50 cm 




APPENDIX 1-D. AVIAN GUILDS 




Avian Guilds (2007 and 2008) 

Aerial Fish Foragers 

Coots and Rails 

Dabbling Ducks/Geese 

Diving Ducks/Grebes/Cormorants 

Belted Kingfisher 

Black Skimmer 

Brown Pelican 

California Least Tern 

Caspian Tern 

Elegant Tern 

Forster's Tern 

Royal Tern 

Unidentified Tern 

White Pelican 

American Bittern 

American Coot 

Sora 

Virginia Rail 

American Wigeon 

Blue-winged Teal 

Brant 

Canada Goose 

Cinnamon Teal 

Gadwall 

Green-winged Teal 

Lesser Scaup 

Mallard 

Mute Swan 

Northern Pintail 

Northern Shoveler 

Snow Goose 

Unidentified Duck 

Wood Duck 

Bufflehead 

Canvasback 

Clark's Grebe 

Common Loon 

Common Merganser 

Double-crested Cormorant 

Eared Grebe 

Greater Scaup 

Hooded Merganser 

Horned Grebe 

Long-tailed Duck 

Pacific Loon 

Pelagic Cormorant 

Pied-billed Grebe 

Red-breasted Merganser 

Redhead 

Ruddy Duck 

Surf Scoter 

Unidentified Scaup 

Western Grebe 




Avian Guilds (2007 and 2008) cont'd 

Gulls 

Herons, Bitterns, and Ibis 

Raptors 

Shorebirds 


Bonaparte's Gull 

California Gull 

Glaucous-winged Gull 

Heerman's Gull 

Mew Gull 

Ring-billed Gull 

Unidentified Gull 

Western Gull 

Black-crowned Night Heron 

Cattle Egret 

Great Blue Heron 

Great Egret 

Green Heron 

Reddish Egret 

Snowy Egret 

White-faced Ibis 

American Kestrel 

Burrowing Owl 

Cooper's Hawk 

Merlin 

Northern Harrier 

Osprey 

Peregrine Falcon 

Red-tailed Hawk 

Sharp-shinned Hawk 

Short-eared Owl 

Turkey Vulture 

White-tailed Kite 

American Avocet 

Black-bellied Plover 

Black-necked Stilt 

Dunlin 

Greater Yellowlegs 

Killdeer 

Least Sandpiper 

Lesser Yellowlegs 

Long-billed Curlew 

Marbled Godwit 

Red Knot 

Red Phalarope 

Red-necked Phalarope 

Ruddy Turnstone 

Sanderling 

Semipalmated Plover 

Short-billed Dowitcher 

Unidentified Dowitcher 

Unidentified Sandpiper 

Unidentified Yellowlegs 

Western Sandpiper 

Western Snowy Plover 

Whimbrel 

Willet 

Wilson's Phalarope 

Wilson's Snipe



Avian Guilds (2007 and 2008) cont'd 

Upland birds 

Allen's Hummingbird 

American Crow 

American Goldfinch 

Anna's Hummingbird 

Barn Swallow 

Belding's Savannah Sparrow 

Bewick's Wren 

Black Phoebe 

Blue-gray gnatcatcher 

Brewer's Blackbird 

Brown-headed Cowbird 

Bushtit 

California Towhee 

Cassin's Kingbird 

Cliff Swallow 

Common Raven 

Common Yellowthroat 

Costa's Hummingbird 

European Starling 

Great-tailed Grackle 

House Finch 

House Sparrow 

House Wren 

Lesser Goldfinch 

Loggerhead Shrike 

Marsh Wren 

Mourning Dove 

Northern Flicker 

Northern Mockingbird 

Northern Rough-winged Swallow 

Orange-crowned Warbler 

Pacific-slope Flycatcher 

Red-winged Blackbird 

Rock Pigeon 

Savannah Sparrow 

Say's Phoebe 

Selasphorus sp. 

Song Sparrow 

Tree Swallow 

Unidentified Gnatcatcher 

Unidentified Goldfinch 

Unidentified Hummingbird 

Unidentified Sparrow 

Unidentified Swallow 

Vaux's Swift 

Violet-green Swallow 

Western Kingbird 

Western Meadowlark 

White-crowned Sparrow 

White-throated Swift 

Wilson's Warbler 

Yellow-rumped Warbler 




APPENDIX 1-E. AVIAN ABUNDANCE BY ZONE IN 2008 


Avian Abundance by Zone for all 2008 Surveys Combined 

Total Future Full Tidal Basin FFTB Full Tidal Basin FTB Muted Tidal Basin MTB Pocket MSeasonal Ponds SP 

14 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 63 Total 68 69 70 71 72 73 Total 41 42 45 46 47 48 49 50 66 Total Marsh 2 9 10 11 12 13 Total 

Allen's Hummingbird 24 1 4 1 1 7 3 1 6 1 11 6 6 

American Avocet 465 2 14 4 1 13 1 2 7 6 3 53 4 17 1 12 6 40 1 50 5 56 166 2 13 131 4 150 

American Bittern 1 1 1 

American Coot 1710 98 15 84 132 54 2 162 11 52 1 27 638 42 42 2 2 4 430 88 434 26 48 596 

American Crow 92 2 3 1 1 5 2 14 7 2 5 14 2 20 3 13 1 39 19 5 1 6 

American Goldfinch 29 7 2 11 20 3 6 9 

American Kestrel 10 1 1 2 4 1 1 2 1 1 1 3 

American Pipit 41 1 2 10 17 2 8 1 41 

American Wigeon 1329 16 16 4 8 64 248 18 23 21 35 2 3 458 59 5 2 8 74 4 8 9 4 53 4 82 437 8 39 203 6 22 278 

Anna's Hummingbird 79 2 1 1 2 1 16 4 1 2 4 34 1 1 4 3 1 3 9 3 1 1 2 27 7 1 8 1 10 

Barn Swallow 231 3 4 3 1 5 4 20 13 2 27 10 7 13 15 2 129 3 8 11 5 27 24 6 4 6 3 2 45 12 10 6 2 18 

Belding's Savannah Sparrow 1082 29 45 6 16 1 9 9 4 2 8 6 2 38 7 42 44 54 15 9 1 9 31 39 7 433 20 5 1 8 9 10 53 64 56 47 51 21 43 57 26 13 378 24 27 24 25 79 24 15 194 

Belted Kingfisher 7 1 1 2 1 1 4 

Bewick's Wren 8 1 3 2 6 2 

Black Phoebe 95 1 2 2 1 3 1 4 5 9 3 6 4 3 2 46 1 1 2 4 1 1 10 2 3 4 25 7 1 2 10 2 15 

Black Skimmer 887 1 1 13 7 233 611 3 15 882 1 1 1 3 1 

Black-bellied Plover 3995 200 2 1 203 69 928 1339 53 389 200 2978 346 1 1 348 1 1 464 465 

Black-crowned Night Heron 44 1 1 2 1 5 1 2 2 5 1 2 1 4 30 

Black-necked Stilt 795 8 17 2 8 7 27 2 2 3 28 4 31 10 28 4 172 22 6 3 5 389 20 24 2 11 57 17 4 36 22 21 15 26 141 22 21 9 15 124 11 6 186 

Blue-gray gnatcatcher 7 1 1 1 1 4 1 1 2 2 

Blue-winged Teal 72 2 1 3 4 4 48 2 50 13 2 2 

Bonaparte's Gull 6 1 1 1 3 4 1 1 

Brant 2 1 1 2 

Brewer's Blackbird 32 32 32 

Brown Pelican 163 1 126 1 9 23 160 3 

Brown-headed Cowbird 3 3 3 

Bufflehead 315 2 2 1 5 5 8 3 26 18 32 57 42 42 191 3 3 1 2 9 52 1 1 2 9 16 8 37 

Burrowing Owl 2 2 2 

Bushtit 71 50 6 56 1 14 14 

California Gull 639 2 1 6 1 6 16 11 108 82 1 147 237 586 5 1 3 2 11 2 1 2 21 24 

California Least Tern 87 1 1 1 4 3 1 2 1 1 2 17 6 7 2 17 9 3 44 7 2 1 2 4 16 3 1 6 7 

California Towhee 15 4 3 3 10 2 3 3 

Canada Goose 50 2 2 2 1 1 5 1 2 16 2 23 25 2 2 4 3 3 

Caspian Tern 186 2 1 1 3 7 2 2 88 31 9 132 3 3 4 3 33 2 2 40 

Cassin's Kingbird 7 2 1 1 4 2 2 1 

Cattle Egret 2 1 1 1 1 

Cinnamon Teal 120 4 2 6 1 4 1 4 2 13 6 2 45 9 34 10 53 5 2 9 6 17 

Clark's Grebe 1 1 

Cliff Swallow 369 7 8 4 1 3 3 2 4 1 2 3 7 6 41 6 8 8 10 6 13 143 12 3 21 21 57 16 6 39 22 5 3 8 30 129 1 5 1 2 24 2 5 39 

Common Loon 2 2 2 

Common Merganser 1 1 1 

Common Raven 16 2 1 3 6 4 1 1 6 4 

Common Yellowthroat 91 3 1 34 1 5 44 1 3 1 5 1 2 1 14 5 28 28 

Cooper's Hawk 6 1 1 1 1 4 1 1 1 

Costa's Hummingbird 2 1 1 1 

Double-crested Cormorant 284 2 3 1 7 1 14 7 20 152 3 6 13 201 5 4 4 2 5 2 3 1 26 34 4 5 9 

Dunlin 273 2 3 3 8 62 30 110 48 1 251 3 8 11 3 

Eared Grebe 177 7 8 15 2 1 11 1 45 12 23 16 14 11 76 5 2 7 13 2 25 2 7 36 

Elegant Tern 2786 4 1 1 2 4 2 14 14 35 1838 647 92 126 2752 1 3 5 4 13 5 1 1 2 

European Starling 71 4 1 1 11 2 5 5 2 11 1 7 2 52 1 2 8 4 3 18 1 1 

Forster's Tern 235 2 2 2 1 1 8 33 26 62 2 40 2 165 1 2 1 6 2 2 14 26 4 4 12 2 22 

Gadwall 681 13 18 1 4 50 67 12 31 2 41 22 2 9 272 2 4 2 8 16 7 15 11 5 2 2 42 50 14 2 24 200 10 51 301 

Glaucous-winged Gull 2 2 2 

Great Blue Heron 69 2 1 2 1 1 1 1 1 2 1 13 11 2 2 4 3 22 4 3 3 3 3 3 19 11 1 1 2 4 

Great Egret 132 7 1 2 2 1 1 1 1 16 24 5 11 15 55 1 4 3 9 2 2 2 6 1 30 20 1 10 11 

Greater Scaup 3 2 2 1 1 

Greater Yellowlegs 104 2 1 3 7 2 4 19 16 16 2 4 1 39 2 1 1 2 2 26 34 9 1 1 1 3



Great-tailed Grackle 45 1 2 17 20 25 25 

Green Heron 5 1 1 1 1 2 1 1 

Green-winged Teal 536 35 6 13 9 16 19 2 100 6 2 8 2 2 287 134 3 2 139 

Heerman's Gull 11 1 1 2 5 1 10 1 

Hooded Merganser 1 1 

Horned Grebe 33 4 9 4 7 6 30 3 

House Finch 930 5 6 3 19 4 3 5 6 5 60 91 32 40 23 35 8 345 19 19 27 83 38 86 121 53 13 6 11 438 2 123 3 126 

House Sparrow 9 7 7 2 2 

House Wren 18 1 6 2 5 1 15 3 

Killdeer 662 14 3 2 19 2 22 20 43 26 26 17 30 10 23 7 4 13 3 284 25 6 2 1 1 35 5 52 21 56 45 7 28 6 1 221 28 1 3 8 36 29 17 94 

Least Sandpiper 210 7 8 9 4 9 4 1 1 43 45 5 12 3 65 41 1 16 1 1 60 30 3 2 7 12 

Lesser Goldfinch 25 7 2 5 14 2 2 5 1 10 1 1 

Lesser Scaup 162 2 2 4 75 79 78 3 3 

Lesser Yellowlegs 11 1 3 4 1 2 2 5 1 1 2 

Loggerhead Shrike 3 1 1 2 2 

Long-billed Curlew 164 1 3 2 1 7 97 6 28 15 146 3 1 4 6 1 1 

Mallard 265 8 3 1 2 8 5 1 1 3 84 7 21 6 150 1 2 2 4 9 3 4 2 2 6 2 5 24 38 2 1 27 10 4 44 

Marbled Godwit 1068 3 3 366 192 219 127 90 994 3 3 49 18 1 19 

Marsh Wren 28 1 8 1 10 1 1 2 4 1 13 14 

Merlin 1 1 1 

Mourning Dove 844 9 12 21 3 2 4 13 6 18 5 41 11 24 91 24 36 36 38 18 114 92 10 628 1 2 3 36 16 20 38 29 43 3 6 1 192 3 2 3 3 8 1 1 18 

Mute Swan 1 1 1 

Northern Flicker 1 1 1 

Northern Harrier 17 2 1 1 4 2 1 3 1 1 2 1 1 6 2 2 2 

Northern Mockingbird 16 3 1 1 1 6 1 13 2 2 1 

Northern Pintail 1018 6 34 40 5 12 8 426 3 36 5 5 23 603 26 4 17 33 80 5 62 67 101 14 10 136 4 3 167 

Northern Rough-winged Swallow 111 2 1 5 5 40 53 3 11 14 2 20 1 3 1 12 39 5 5 

Northern Shoveler 2366 64 28 6 19 2 2 193 4 127 13 87 235 73 34 3 890 1 25 3 23 52 2 25 4 26 2 6 18 83 32 64 6 17 1098 84 40 1309 

Orange-crowned Warbler 3 3 3 

Osprey 9 1 1 2 1 1 2 5 

Pacific Loon 1 1 1 

Pacific-slope Flycatcher 1 1 1 

Pelagic Cormorant 1 1 1 

Peregrine Falcon 10 1 1 1 1 4 2 2 4 1 1 2 

Pied-billed Grebe 51 1 4 2 1 8 11 5 2 18 1 1 22 2 2 

Red Knot 49 13 21 4 3 41 5 3 8 

Red-breasted Merganser 17 7 1 1 3 12 5 

Reddish Egret 11 4 2 2 1 9 2 

Redhead 85 1 7 26 6 10 11 5 66 5 5 1 1 2 5 4 1 2 7 

Red-necked Phalarope 26 1 1 2 1 5 1 15 22 2 2 

Red-tailed Hawk 20 2 1 4 2 3 1 13 2 1 3 2 1 3 1 1 

Red-winged Blackbird 71 2 28 30 41 41 

Ring-billed Gull 356 1 24 3 1 4 1 7 3 44 8 22 17 14 61 4 35 1 1 1 4 46 74 1 1 124 1 4 131 

Rock Dove 10 2 3 5 1 2 3 1 1 1 

Royal Tern 86 1 34 25 17 5 82 1 1 1 2 3 

Ruddy Duck 1169 36 4 43 144 19 19 49 71 3 388 29 3 4 2 38 2 4 6 227 2 425 14 69 510 

Ruddy Turnstone 45 6 10 12 3 9 40 5 5 

Sanderling 252 82 157 4 3 246 6 6 

Savannah Sparrow 819 271 213 2 1 2 1 4 27 3 1 13 2 2 8 8 1 559 6 1 7 1 18 35 10 39 8 22 35 168 29 2 5 24 10 15 56 

Say's Phoebe 41 1 2 1 1 1 1 2 1 1 2 2 15 4 1 1 1 7 3 1 1 1 2 1 9 2 2 3 3 8 

Semipalmated Plover 957 47 19 66 61 26 297 330 7 721 3 1 166 170 

Sharp-shinned Hawk 2 1 1 1 1 

Short-billed Dowitcher 3 3 3 

Snow Goose 1 1 1 

Snowy Egret 271 1 2 4 1 1 1 10 77 23 26 14 2 142 3 8 3 4 9 3 30 88 1 1 

Song Sparrow 65 19 2 21 1 2 1 1 5 38 1 39 

Sora 4 3 3 1 1 

Surf Scoter 325 3 47 42 233 325



Tree Swallow 46 1 1 8 3 10 23 4 4 10 4 14 5 5 

Turkey Vulture 33 1 1 1 1 1 1 1 7 2 1 2 5 1 1 12 14 5 2 2 

Unidentified Dowitcher 2114 2 3 4 57 1 3 17 82 1 4 174 643 12 386 3 1 1045 28 16 24 8 76 802 1 13 3 17 

Unidentified Duck 2 2 2 

Unidentified Goldfinch 1 1 1 

Unidentified Gull 317 5 1 15 1 6 3 2 7 1 2 1 1 1 15 17 22 100 3 2 5 83 14 1 3 8 109 3 1 6 3 5 10 75 100 

Unidentified Hummingbird 1 1 1 

Unidentified Sandpiper 1571 15 15 25 5 16 9 1 12 42 3 8 12 163 995 27 199 52 32 1305 6 29 32 8 10 85 4 11 3 14 

Unidentified Scaup 38 2 2 11 5 5 5 26 10 

Unidentified Shorebird 200 200 200 

Unidentified Sparrow 13 1 4 5 8 8 

Unidentified Swallow 34 4 4 30 30 

Unidentified Tern 12 3 3 3 3 6 6 

Unidentified Yellowlegs 165 1 4 2 1 2 1 11 42 2 5 2 1 52 2 13 1 20 3 37 76 20 3 1 2 6 

Violet-green Swallow 50 3 8 24 10 3 48 2 2 

Virginia Rail 3 3 3 

Western Grebe 7 4 2 1 7 

Western Gull 487 8 1 8 6 1 1 60 13 98 8 24 158 17 136 343 1 5 13 8 7 2 2 1 39 3 4 4 

Western Kingbird 3 2 1 3 

Western Meadowlark 89 1 1 1 1 4 6 6 6 10 4 4 10 5 8 13 6 66 2 1 1 1 8 11 

Western Sandpiper 13305 12 21 3 22 13 90 20 18 50 83 7 339 2100 2506 3127 1527 196 9456 724 2 109 5 2 842 185 3 18 1646 810 6 2483 

Western Snowy Plover 139 3 3 8 17 42 18 26 111 3 6 10 6 25 

Whimbrel 138 5 5 49 19 45 13 6 132 1 

White Pelican 34 15 2 17 1 1 2 2 14 

White-crowned Sparrow 139 3 9 3 2 20 3 7 4 51 10 10 3 1 6 4 33 4 1 4 15 71 4 2 1 3 

White-faced Ibis 2 1 1 2 

White-tailed Kite 3 1 1 2 1 1 

White-throated Swift 4 1 3 4 

Willet 726 3 5 1 1 1 1 1 13 267 54 145 1 62 41 570 3 6 5 6 20 120 3 3 

Wilson's Phalarope 48 3 3 37 37 1 7 8 

Wilson's Snipe 1 1 1 

Wood Duck 1 1 

Yellow-rumped Warbler 81 1 1 1 7 1 14 9 7 1 6 48 1 2 3 6 24 24 

Grand Total 51137 1059 495 82 147 33 300 50 102 30 61 28 2 841 82 1055 964 510 181 1415 179 618 395 375 101 9105 5306 4450 9209 1400 3311 1737 25413 316 502 250 1658 397 544 232 620 114 4633 3745 252 85 219 5967 1287 431 8241



APPENDIX 1-F. FINAL REPORT WESTERN SNOWY PLOVER NESTING AT BOLSA CHICA, ORANGE 

COUNTY, CALIFORNIA 2008 


Western Snowy Plover Nesting 

at Bolsa Chica, Orange County, California 

2008 

Photo by Peter Knapp 

by Peter Knapp and Bonnie Peterson* 


* Merkel & Associates, Inc.

Western Snowy Plover Nesting at Bolsa Chica, 2008 December 2008 

INTRODUCTION 

Bolsa Chica is a coastal lowland area between two mesas, the Bolsa Chica Mesa and the Huntington 

Beach Mesa in Orange County, California (Figure 1). Bolsa Chica, which a century ago was under 

full tidal influence, has started to come full circle. Over 100 years ago, Bolsa Chica was diked-off 

from direct tidal influence but remained below mean sea level, becoming influenced by freshwater 

and a sump for local drainage. In 1978, restoration began on the State’s Ecological Reserve, and 

muted tidal influence was restored to the Inner Bolsa Bay area. At that time, two small islands, 

North Tern Island and South Tern Island, were created for nesting California least tern (Sternula 

antillarum browni), a State and Federal endangered species. 

In 1997, the Bolsa Chica lowlands were acquired into public ownership. This marked the beginning 

of a multi-agency effort to design, evaluate, and implement a plan for restoring the fish and wildlife 

habitats which had been cut off from the ocean for a century and an operating oil field for 50 years. 

Construction of the restoration project began in Fall 2004 and was completed in August 2006. 

By the 2006 breeding season, 3 new nest sites were available for nesting and augmented the preexisting 

North and South Tern Islands in Inner Bolsa Bay. The new ocean inlet, referred to as the 

Full Tidal Basin, was opened after the conclusion of the breeding season in August 24, 2006. The 

Full Tidal Basin is now subject to water level rise and fall that matches the unequal semi-diurnal tidal 

range of southern California’s ocean waters. 

The purpose of this investigation is to continue to improve the level of knowledge about the western 

snowy plover (Charadrius alexandrinus nivosus), a federally listed, threatened species that currently 

uses Bolsa Chica, and to attempt interim management actions to benefit the reproductive success of 

this species. In addition, this study will aid in assessing the success of the restoration projects and 

allow for modifications that would enhance utilization and increase reproductive success of the 

western snowy plover. This annual study was first initiated in 1997. This report addresses the 2008 

snowy plover breeding season at Bolsa Chica. 

BACKGROUND AND CURRENT STATUS 

The western snowy plover is a sparrow-sized, white and tan colored shorebird with dark patches on 

either side of the neck, behind the eyes, and on the forehead. The coastal western snowy plover 

population is defined as those individuals that nest adjacent to or near tidal waters and includes all 

nesting colonies on the mainland coast, peninsulas, offshore islands, adjacent bays, and estuaries. 

The breeding range of the coastal population of the western snowy plover extends along coastal 

beaches from the southern portion of Washington State to southern Baja California, Mexico. The 

Pacific coast population of the western snowy plover is reproductively isolated from the interior 

populations. 

The breeding season of the western snowy plover extends from March 1 through September 15. 

Generally, 3 eggs are laid in a nest on the ground, which consists of a shallow depression scraped in 

the substrate. Some nests are lined with plant parts, small pebbles, or shell fragments. Both sexes 

incubate the eggs for an average of 27 days. Snowy plovers will renest after loss of a clutch or 

brood. Snowy plover chicks are precocial and leave the nest within hours of hatching in search of 

food. The tending adult(s) provide danger warnings, thermo-regulation assistance, and guide the 

chicks to foraging areas, but do not provide food to their chicks. Broods rarely stay in the immediate 

area of the nest. Young birds are able to fly within approximately 31 days of hatching. 


Study 

Area 

 

 

 

 

Meters 

0 250 500 1,000 

Figure 1. Bolsa Chica Vicinity Map

Western Snowy Plover Nesting at Bolsa Chica, 2008 December, 2008 

Double brooding and polyandry are the typical. Snowy plover females may leave very young chicks 

to find another mate. The male typically tends the brood until the chicks fledge. Western snowy 

plover adults and young forage on invertebrates and insects (Page et al. 1995, Tucker and Powell 

1999) along intertidal areas, beaches in wet sand and surf cast kelp, foredune areas of dry sand above 

the high tide, on salt panne, and edges of salt marshes and salt ponds. The snowy plover is primarily 

a run and glean type of forager. 

Poor reproductive success resulting from human disturbance, predation, and inclement weather, 

combined with permanent or long-term loss of nesting habitat to urban development and the 

encroachment of introduced beach grass, has led to the decline in active nesting colonies as well as 

an overall decline in the breeding and wintering population of the western snowy plover along the 

Pacific coast of the United States. In southern California, the very large human population and the 

resultant beach recreation activities by humans have precluded the western snowy plover from 

breeding on historically used beach strand habitat. As a result of these factors, the Pacific coast 

population of the western snowy plover was federally listed as threatened with extinction on March 

5, 1993 (Federal Register 1993). 

Studies from 1997-2008 have examined the scope, magnitude, and problems of snowy plover 

breeding activity at Bolsa Chica, before, during and after completion of the restoration project. 

BOLSA CHICA STUDY AREA 

The study area includes several snowy plover nesting areas within Bolsa Chica. These nesting areas 

include: Seasonal Ponds (Cells 1 through 37), North Tern Island (NTI), South Tern Island (STI), 

Nest Site 1 (NS1), Nest Site 2 (NS2), and Nest Site 3 (NS3) (Figure 2). Some areas in the vicinity of 

the Bolsa Chica study area were not surveyed in this study, although western snowy plovers may 

have used the habitats for foraging or loafing. Those areas are the ocean beach immediately to the 

west at Bolsa Chica State Beach and Inner Bolsa Bay to the west of West Levee Road with the 

exception of NTI and STI (Figure 2). The study area also did not include Cell 64 (the Edwards 

Thumb), which remains in private ownership and a different oil lease. 

The Seasonal Ponds are demarcated into subareas (cells) by the network of slightly elevated roads 

constructed decades ago for access to the oil wells. These cells were numbered and form the basis 

for observer navigation, nest mapping, and data recording. Each cell is unique in configuration and 

area. The approximate areas of some key cells are: Cell 10 (17 acres) and Cell 11 (54 acres). The 

seasonal ponds are predominantly soil or salt panne and the most dominant plant species is 

pickleweed (Sarcocornia pacifica). Some cells are thickly vegetated with pickleweed and considered 

unsuitable for western snowy plover nesting (Cells 41 through 50). Similarly, areas inundated by 

water during most of the breeding season (Cells 30 and 38) are unsuitable for nesting but the margins 

were regularly checked for nesting plovers. Cells 11, 13, and 32, that were commonly utilized in 

previous years were inundated this year and were not available for snowy plover nesting. This 

caused greater use of NS1 by the plovers. 

NTI and STI are well-established created islands under muted tidal influence within Inner Bolsa Bay. 

The surface is dredge spoil with a developed boundary of intertidal or salt tolerant vegetation. STI is 

a regular breeding area for least terns but has also has several snowy plover nests per season. NTI 

has been used primarily by larger terns (elegant, Forester’s, royal, and Caspian) and black skimmers 


2008 Nest Locations 

!( Nest 

μ 

!( Nest - Fledged at least 1 

!> Predated or Abandoned 

!> Unknown Outcome 

Nest Sites 

37 

Roads 

39 

38 

63 

34 

35 

36 

PM 

50 

66 

47 

 

46 

48 

49 

69 

45 

42 

 

 

70 

41 

 

 

40 

72 

32 

30 

!( ! > !( 

!( 

29 

31 28 

19 

33 

!( 

! > 

!( !( !( 

!( !( 

!( 

!( 

!( 

!( 

!( !( !( !( 

!( 

!( 

!( 

!( 

!( 

20 

14 

27 

26 

21 

9 

25 

13 

22 

 

 

10 

2 

24 

23 

!( 

12 

 

 

11 

68 

!( !( !( !( 

!( 

!( 

!( 

! > 

! > ! > ! > 

! > 

! > !( 

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!!! >>> 

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!( 

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!( 

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!( 

!( 

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71 

 

 

!( 

!! (( 

!( 

 

73 

 

Meters 

0 100 200 400 600 

 

Figure 2. Distribution of Western Snowy Plover Nests in 2008 at Bolsa Chica


(Rynchops niger), but after an absence of plover nests for 10 years, at least 1 and probably 2 plover 

pairs nested on NTI in 2008. One nest was confirmed and subsequently abandoned due to conflict 

between the plovers and elegant terns (Thalasseus elegans). 

Snowy plovers at North Tern Island are being kept from their nest by a large flock of elegant terns. The nest 

pictured was subsequently abandoned with 3 eggs in the nest. 

NS1 is a large linear nesting area between Inner Bolsa Bay and the Full Tidal Basin that was built 

during the creation of the Full Tidal Basin. The surface is dredge spoil that forms a flat surface that 

extends from the West Levee Rd. towards the basin. The shoreline of the nest site is now under full 

tidal influence. In 2008, vegetation lightly covered much of the site, including beach evening 

primrose (Camissonia cheiranthifolia), beach sand-verbena (Abronia umbellata var. umbellate), 

saltgrass (Distichlis spicata), alkali heath (Frankenia salina), pickleweed, coastal deerweed (Lotus 

scoparius), five-hook bassia (Bassia hyssopifolia) and 3 types of common iceplant 

(Mesembryanthemum sp.). Efforts were made during the winter and spring to remove much of the 

iceplant but it still persisted in patches throughout the site. The area along the northeastern shoreline 

lacks vegetation or debris that is normally found in a tidal area. Pickleweed is slowly spreading on 

this shoreline. 

NS2 and NS3 are also newly created sites that are within Cell 42 and Cell 14, respectively. NS3 is 

within the Seasonal Ponds and NS2 is located in the Muted Tidal Basin. These sites were built up 

with fill and covered with sand. Winds have blown the sand from the surface of NS3, and rainfall 

has eroded NS2. There is very little live vegetation on either nest site. Foraging areas for snowy 

plover chicks are not readily available on these nest sites; therefore, they must leave the site 

immediately upon hatching to find foraging areas in the adjacent cells or at the foot of the raised 

nesting site. 



Photo by B. Peterson 

Photo by B. Peterson 

Nest Site 1 (NS1) nesting area (left) and shoreline (right) in October 2008 after the breeding season. 

Public access is not allowed on any of the western snowy plover nesting sites. The human presence 

in the study area is mostly related to the operation of the oil field, consisting of large and small oil 

service vehicles and small work crews along the roads and well pads. 

STUDY METHODS 

Beginning late-March, Peter Knapp (the primary surveyor), assisted by Wally Ross, Kelly O’Reilly 

(California Department of Fish & Game (CDFG)), and Bonnie Peterson (Merkel & Associates) 

surveyed for nesting western snowy plovers a minimum of twice a week, but most often on a daily 

basis. Data collected during this study included the gender of the incubating adult, length of 

incubation (days), number of eggs in the clutch, condition of the nest (e.g. signs of disturbance), and 

the fate of each nest (hatched, predated, or abandoned). Observations were also recorded of western 

snowy plover distribution, throughout the study area, not just those birds associated with nests. 

The large majority of suitable western snowy plover nesting habitat in the Seasonal Ponds was 

visible from the road network. Usually between 7 am and noon, the observer(s) would slowly drive 

in a motor vehicle along the roads that subdivide this area. Frequent stops were made to examine 

specific areas adjacent to the road with binoculars or spotting scope without exiting the vehicle. In 

this manner, it was possible to discover most nests within a few days of eggs having been laid. Most 

of the time, a nest was evident when an adult was incubating. Other times the adult was foraging or 

preening near the nest and soon returned to it. The observer would occasionally exit the vehicle in 

order to inspect an area not visible from the road or to verify the presence of eggs or chicks in a nest. 

Close examination of nests was usually conducted only once or twice per nest. 

STI was surveyed by vehicle from the West Levee Road and on foot as part of the least tern surveys. 

NTI is used primarily by nesting elegant terns and black skimmers and was surveyed from the West 

Levee Road. 

NS1, NS2, and NS3 are sectioned by markers which form the basis for data recording. NS1 is 

sectioned south to north from A though CC. NS1 was surveyed by vehicle, in the same manner as 

the Seasonal Ponds, either from the West Levee Road or the eastern slope of NS1. Due to nesting 

patterns of least terns, black skimmers, and other terns, vehicle surveys were suspended mid-May. 



NS1 was also partially surveyed on foot as part of least tern surveys from marker CC south to marker 

M until surveys had to be suspended in July, due to excessive nesting activity by the terns and 

skimmers. Each nest located on NS1 was marked with numbered tongue depressors, mapped for 

ease of relocation on subsequent visits, and a mini exclosure was placed over the scrape. NS2 was 

surveyed by vehicle from the East Levee Road weekly using a spotting scope and once a month on 

foot. There was no nesting activity on NS2 this season although plovers were present and created 3 

or 4 scrapes. NS3 was surveyed by vehicle from the north end of the site. 

On all sites other than NS1, it was usually possible to follow the movements and determine the fate 

of chicks of each brood since there was dispersion over space and time sufficient to differentiate 

between broods. In a few cases banded adults identified specific broods, although banding of chicks 

has not been done at Bolsa Chica since 2000. Broods were observed 2 - 7 days per week. These 

regular brood observations were conducted to determine chick survival or fledgling production, as 

well as to detect movement between cells and use of specific cells for brood rearing. Due to high 

nesting activity on NS1 in 2008 following broods along such a long narrow reach was difficult. 

Effort was still made to determine the number of fledglings but it was often difficult to assign them 

to a specific nest. 

A Range-wide, Breeding Season Window Survey was conducted at Bolsa Chica in May 2008. The 

survey was conducted in the same manner as in previous years and in accordance to the guidelines 

set out in the Recovery Plan for the Pacific Coast Population of the Western Snowy Plover (USFWS 

2007). 

PROTECTION FROM PREDATORS 

Photo by P. Knapp 

Photo of American crow perched on an active snowy plover nest covered 

with a mini-exclosure (ME). 

Once a nest was discovered, 

a welded wire miniexclosure 

(ME) was 

anchored in place over the 

top of the nest and left in 

place until the eggs in the 

nest hatched. The MEs are 

28-inches in width on all 

four sides and 16-inch in 

height. These dimensions 

have proved effective in 

deterring predation by 

corvids and coyotes (Canis 

latrans). 

Observations were made of 

potential predators during 

the surveys. Predator 

management actions were 

then enacted commensurate 

with the threat to snowy plover breeding activity by that specific predator. Predator management has 

been a necessary recovery action for the California least tern for decades. In places, such as Bolsa 

Chica, where snowy plover nests in proximity to the least tern, predator management activities on 



behalf of one species will also benefit the other species. In 2008, predator management was 

undertaken by Wally Ross under contract to U.S. Fish and Wildlife Service (USFWS). 

In 2008, as in past years, simulated nest scrapes were constructed using quail eggs injected with 

bitter tasting, non-lethal contents. This aversion technique has been successfully used in previous 

years in an attempt to deter coyote depredation of snowy plover eggs. The use of “aversion” nests 

was intended to teach coyotes to leave ME-covered eggs alone, without harming or removing 

coyotes. From February 1 through April, these “aversion nests”, with 3 baited eggs each, were 

constructed in areas where snowy plovers had nested in the past. Some nests were covered with an 

ME and some were not. The use of aversion nests and the ME contribute greatly to low egg 

predation in 2008. Chick predation by coyote in 2008 will be discussed in a following section. 

NS1 was watered during the winter months, prior to the 2008-breeding season, to aid the germination 

of existing native plant seeds. Non-natives were removed by hand and with the use of herbicide. 

These efforts provided additional cover for the young snowy plover chicks. Clay roof tiles were 

placed on NS1 and NS3 to provide further shelter for young chicks. 

RESULTS AND DISCUSSION 

NUMBERS OF MALE AND FEMALE SNOWY PLOVERS 

During May 2008, a range-wide breeding season window survey was conducted. The total number 

of snowy plovers present at Bolsa Chica was 50 adults: 22 female and 28 male (Table 1). This is a 

higher count than in 2007, but has not yet reached the highest counts seen in 2005 (62) and 2006 

(65). 

Table 1. Males, Females, Nests and Fledgling Production 1997-2008 

Year Females Males 

Total 

Total % Chick 

Fledglings 

Nests 

Fledge/Nest Survival 

Fledge/Male 

2008 22 28 67 57-109* 0.85-1.62* nd 2.0-3.9* 

2007 18 12 50 25 0.50 19.2 2.1 

2006 27 35 71 64 0.90 38.5 1.8 

2005 25 41 51 75 1.47 65.2 1.8 

2004 25 20 65 79 1.22 53.0 4.0 

2003 15 16 32 44 1.38 57.9 2.8 

2002 19 20 50 27 0.54 36.0 1.4 

2001 19 18 55 57 1.04 90.5 3.2 

2000 15 16 39 42 1.08 85.4 2.6 

1999 12 11 38 23 0.61 32.4 2.1 

1998 11 16 34 25 0.74 37.3 1.6 

1997 14 20 30 nd nd nd nd 

Fl = fledglings, nd = not determined 

* based on minimum/maximum numbers of fledglings 

NEST DISTRIBUTION AND CHRONOLOGIES 

The distribution of nests indicates that NS1 and the Seasonal Ponds were the preferred plover nesting 

sites in 2008. NS1 had more than half (55%) of all the nests and the Seasonal Ponds had 30% of the 



nests. (Figure 2, Table 2). The most utilized cells were Cell 22 (9%), Cell 10 (4%), Cell 12 (4%), 

Cell 19 (6%), and several roadways (4%) were utilized for nesting this year. There was one nest on 

NTI and 4 nests on STI. 

Appendix 1 provides the cell location, start and end dates, nest fates, eggs and chicks produced for 

each nest. 

Distribution of nests on the Seasonal Ponds fluctuates annually (Appendix 2); however, in 2008 

many of the cells that were commonly used, such as Cell 13 and Cell 11, were not available for 

nesting plovers in 2008 due to high water levels. Typically these cells collect water during the winter 

rains, but later drain out by gravity into Freeman Creek, exposing dry salt panne prior to the breeding 

season. 

In 2008, delayed drainage of the Seasonal Ponds occurred as a result of the inability of Freeman 

Creek to drain to the Full Tidal Basin, due to reduced tidal prism associated with the flood shoal that 

had formed in the inlet of the basin. A pump-down of water levels was undertaken in May 2008 to 

drain water levels; however, it was too late in the nesting season to make these cells available for 

nesting plovers. Cells 9, 10, 12, 19, and even the roadways were utilized by the snowy plover in 

order to find dry, suitable nesting areas. Figure 2 shows the location of all nests located in the Bolsa 

Chica study area. 

Table 2. 2008 Nest, Nest Fate, and Reproductive Success Distribution by Cell 

Location Total Nests Nests Failed 

Nests Hatched 

(# chicks) 

Fledglings 

Nest Site 1* 37 1 36 (100) 33-83 

Seasonal Ponds: 20 2 18 (51) 18 

Cell 9 1 0 1 (3) 3 

Cell 10 3 0 3 (8) 1 

Cell 12 3 0 3 (8) 6 

Cell 19 4 1 3 (9) 3 

Cell 22 6 1 5 (15) 2 

Road 3 0 3 (8) 3 

Nest Site 3 5 0 5 (14) 3-5 

North Tern Island 1 1 0 (0) 0 

South Tern Island 4 1 3 (9) 3 

Total 67 5 62 (174) 57-109 

*Nests were not monitored on NS1 for the entire season; therefore, nests failed and nests hatched are for known nests (minimum 

number). The number of fledglings is based on the minimum and maximum number of fledglings for NS1. 

The number of nests on NS1 has increased dramatically from 14 nests in 2006, the first year the site 

was available, to 37 in 2008 (Appendix 2). Reproductive success remained consistent on NS1 with a 

fledge rate of at least 0.89 (fledge/nest). The increased usage of NS1 has been balanced out by a 

decreased use of the Seasonal Ponds. The reproductive success in the Seasonal Ponds was very low 

in 2007 at 0.28, increasing to 0.90 in 2008, even with suboptimal conditions. This would 

demonstrate that Bolsa Chica has not reached its highest potential for nesting snowy plovers. 

The Seasonal Pond Cells, in addition to the nesting areas, are also the primary feeding areas for 

hatched plovers other than those from STI and NS1. More than one cell maybe used by a brood and 

often a brood will travel to another cell within one or two days of hatching. As an example, although 



there were no nests in Cell 11 this year, at least 6 broods fed in this cell and most of the chicks 

fledged. 

The State and Federal Endangered California least tern also nests at Bolsa Chica. In 2006, they 

nested on STI and on the newly created NS1 and have continued this nesting pattern through 2008. 

Snowy plover egg-laying typically begins several weeks before the least tern begins its egg-laying. 

This has been the case at Bolsa Chica. The two species tolerate the co-location of their nests. 

Black skimmers, elegant, royal (Thalasseus maximus), California least, Caspian tern (Hydroprogne 

caspia), and American avocet (Recurvirostra Americana) all nested on NS1 in 2008. These species 

typically nest on NTI. In June 2007, the black skimmers and some of the elegant terns abandoned 

that nesting site and moved to NS1. The tight colonial style of nesting of the terns and black 

skimmers did not exclude the snowy plover from any portion of the nesting area. However, it is 

suspected that their presence on NS1 had an effect on the overall reproductive success of the snowy 

plover once the nests hatched and the chicks left the protection of the ME. Black skimmers are 

known to be predators of tern chicks (Gochfeld and Burger 1994). 

In 2008, the first plover nest was initiated March 17, which is early compared to previous years. 

Snowy plover nesting rose to its peak by mid-April (Figure 3). Twenty-five (37%) nests had been 

initiated by May 1, which is a greater number of nests than in all previous years of the study. Half of 

the nests had been initiated by May 12, 2 weeks earlier that in 2007. The last nest hatched on August 

9 with no new nest being initiated after July 16 (Figure 4) which is comparable to past years. 

25 

# of Active Nests 

20 

15 

10 

5 

97-04 ave 

2005 

2006 

2007 

2008 

0 

Survey Date 

17-Aug 

11-Aug 

2-Aug 

27-Jul 

21-Jul 

14-Jul 

9-Jul 

2-Jul 

25-Jun 

19-Jun 

15-Jun 

9-Jun 

3-Jun 

Figure 3. 1997-2008 Bolsa Chica Active Nest Chronology. 

27-May 

23-May 

18-May 

13-May 

6-May 

1-May 

27-Apr 

22-Apr 

17-Apr 

11-Apr 

4-Apr 

29-Mar 

23-Mar 

15-Mar 

EGG, CHICK, AND FLEDGLING PRODUCTION 

All 67 nests in 2008 were judged to be complete clutches with the exception of Nest #4 in Cell 22 

and Nest #21 on NS1, which were both predated prior to the completion of egg laying and the 

placement of the ME. Only 4 completed clutches were 2-egg clutches, while 61 were 3-egg clutches 

(Appendix 1). Three nests were abandoned and appeared to be unrelated to each other. Two were 



initiated in mid April, one on NTI and one on STI. The third abandoned nest was initiated in mid- 

July in Cell 19. 

14 

12 

# of Nests 

10 

8 

6 

4 

2 

initiated 

hatched 

predated/lost 

0 

Mar 16-31 

Apr 1-15 

Apr 16-30 

May 1-15 

May 16-31 

Jun 1-15 

Jun 16-30 

Survey Time Period 

Jul 1-15 

Jul 16-31 

Aug 1-15 

Figure 4. Biweekly Western Snowy Plover Nest Initiation, Hatching, & Loss at Bolsa Chica in 


The abandoned nest on NTI was caused by harassment of the plover pair by elegant terns. The 

plovers continuously failed to reach the protection of the ME over their eggs and after 2 days 

abandoned the nest. In 2007, on NS1, 2 plover nests protected by an ME survived to hatch amongst 

the elegant terns. 

The nest abandoned on STI (Nest #19) was incubated by banded female WWYY. Prior to the 

abandonment of Nest #19, Nest #12 hatched, but the brood was unattended by an adult. The chicks 

from Nest # 12 gravitated to Nest #19 and, after initially attempting to drive off the chicks, the 

female (WWYY) began to brood these chicks and to simultaneously incubate her own eggs. It was 

apparent that she was confused by the situation and the next day after an adult from Nest #12 

appeared and brooded its chicks, the female abandoned her Nest #19. 

The nest in Cell 19, Nest # 65, was abandoned for unknown reasons. Subsequent examination of 

eggs revealed semi-developed chicks. 

A total of 193 snowy plover eggs were produced at Bolsa Chica in 2008, with 19 eggs abandoned, 

predated, or failing to hatch. From the 193 total eggs, 174 chicks were produced. Of these 174 total 

chicks produced in 2008, a minimum of 57 chicks (32.8%) and a maximum of 109 chicks (62.6%) 

were estimated to have survived to fledge (Table 2). This is the highest number of hatched nests and 

potentially the highest number of fledglings recorded at Bolsa Chica. Even the minimum number of 

fledglings is surpassed only by 2004, 2005, and 2006 (Figure 5). Sixty-two nests survived to hatch 

with a hatching success rate of 92.5%. This is the highest hatching success rate in all years surveyed 

with the exception of 2007 at 96.0%. 



The total fledgling count was difficult to determine in 2008 due to the nesting activity on NS1; black 

skimmers, elegant terns, royal terns, Caspian terns, and American avocets all nested on NS1 along 

with the California least tern and the western snowy plover. During July and August, there was so 

much activity on the nest site that walking the site to locate nests was no longer possible and all 

human activity on the site was stopped. The total fledgling count for 2008 was estimated to be 

between 57 and 109. This minimum count is an increase over the results for 2007 and is comparable 

to the higher counts in previous years. 

# Nests 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

Hatched Nests 

Failed Nests 

Fledglings 

1997* 

1998 

1999 

2000 

2001 

2002 

2003 

Year 

Figure 5. Comparison of Number of Western Snowy Plover Hatched Nests, Failed Nests, and 

Fledglings 1997-2008 at Bolsa Chica 

In 2008, 9 dead eggs were observed, excluding eggs in abandoned nests. With 193 total eggs laid in 

2008, 4.7% of total eggs were dead eggs. No laboratory analysis was made of these dead eggs. In 

the previous 10 years the average percent dead eggs is 4.2% (60/437). 

In this study, when one or more eggs of a clutch hatch, several days are allowed to pass before any 

egg(s) that may have been abandoned are removed. No apparently abandoned eggs have been seen 

to hatch. 

2004 

2005 

2006 

2007 

2008** 

* fledglings not determined in 1997 

** minimum number of fledglings presented for 2008 

BROOD TRACKING 

Due to the chronological and geographic spacing of each brood, it is often possible to locate and 

identify individual broods over the period before they fledge. As generally seen in prior years, in 

2008 each brood tended to stay together and the males prevented overlap or co-mingling with other 

broods. There were confrontations between the males if the broods wondered to close together or 

tried to take advantage of the same resources (see photo below). 

Broods hatched from NS3 relocated within days to other locations to seek food. Snowy plovers 

readily used the roads of Bolsa Chica to cover distances of 1/3 to 3/4 mile. In the seasonal ponds, 

broods would move about or change cells readily but could generally be identified. Broods on NS1 



were not tracked on a regular basis to avoid possible disturbance of other nesting birds on the site 

(least, elegant, royal, and Caspian terns, and black skimmers). 



Territorial dispute between two male snowy plovers 

OBSERVATIONS OF BANDED ADULTS 

A male (RBRP) hatched at Moss Landing in 2001 and has bred every year at Bolsa Chica since 2003 

and in 2008 had 3 nests; two on NS1 (Nests #6 and #50) and one in Cell 10 (Nest #64). He produced 

5 fledglings this year. This male has not been seen in the area during the non-breeding seasons. The 

only winter record was at Pt. Magu in February 2006. 

A male (WNGY) has nested at Bolsa Chica every year since 2004. This male was banded at 

Guadalupe Dunes near Pismo Beach in 2003. He has wintered at Surfside, Orange County and Bolsa 

Chica State Beach for the past 3 years. In 2008 he had a minimum of 2 nests on NS1 and a third 

(Nest #65 that was abandoned) in Cell 19. 

A female (WWYY) banded as an adult at the South Spit, Humboldt Bay in 2006, nested twice at 

Bolsa Chica on STI in 2007 and 3 times in 2008 including once on STI (Nest #19), NS1 (Nest #43) 

and the road between Cells 2 and 10 (Nest #63) in the Seasonal Pond area. 

A female (SKM), banded at Camp 

Pendleton (year unknown), wintered at 

Surfside, Orange County in 2007/8 and 

bred at least once at Bolsa Chica in 2008 

(Nest #10). 

Three other banded adults nested at Bolsa 

Chica in 2007 and 2008, but were 

identified by only a USFWS band. Two 

were females and the other a male. One of 

the females nested twice with male 

Photo by P. Knapp (RBRP) on NS1 in 2008. 

Snowy plover male banded (RBRP) and female banded 

with USFWS band only. 

Two chicks from Nest #6 were handreared 

at the Wetlands and Wildlife Care 

Center of Orange County and were banded YNYR and YNWW. They were released in Cell 11 in 



early June and were seen until late July at Bolsa Chica. YNYR was subsequently seen at Batiquitos 

Lagoon and later at the Tijuana Estuary. A third chick was successfully hand-reared at the care 

center and was released on Bolsa Chica State Beach unbanded. The later chick was from Nest #67 

and was found unattended 2 days after its siblings hatched and were led away into another cell. 

Other banded bird sightings not breeding at Bolsa Chica were as follows: WBRW on March 24; 

RWRW on April 24 through 26; RAGY and VKRR on July 19; BBVG on August 6; VVVR on 

August 10; YYGW on August 11; PGVG on August 19; and OYLL on August 27. 

PREDATION 

In 2008, 2 of the 67 nests were depredated. Nest #4 in Cell 22, with 1 egg, was a probable loss to a 

corvid. Nest #21 on NS1, with 1 egg, was a probable loss to a gull. Neither nest had an ME placed 

over it as confirmation of the nest was performed after the eggshell remnants were discovered. Three 

nests were abandoned. Sixty-two nests hatched. The 2008 proportion of nests hatching, 62 out of 

67, was 93%. The low rate of nest loss and high degree of chick production is attributable in 2008 to 

the following management actions: a) deployment of ME’s to deter corvid and coyote predation, b) 

the use of “aversion” nests to deter predation by coyotes and, c) regular monitoring. 

The minimum fledgling estimate per nest (0.85) is slightly below the average (0.95) of the study 

years. The maximum fledgling estimate per nest (1.62) would exceed the previous high of 1.47 in 

2005. 

Of the 67 nests, 24 are known to have not fledged chicks. Five of these 24 did not produce chicks (2 

depredated and 3 abandoned). Of the 19 known nests producing chicks but not producing fledglings, 

one brood (Nest #57) was depredated by gulls and one brood (Nest # 25) by coyote. On the 

remaining 17 broods predation was not observed but the potential predators were: red-tailed hawk 

(Buteo jamaicensis) on STI (2 nests), American kestrel on Seasonal Ponds (12 nests) and black 

skimmers on NS1 (5 nests). Loggerhead shrikes were not present in 2008. 

Red-tailed hawks were regularly present at Bolsa Chica, but no hawk nests were known to be present 

in 2008. Red-tailed hawks were present continuously on the power poles opposite STI. Although 

there was no documented take of snowy plover chicks by red-tailed hawks, one took at least one least 

tern chick from STI from this perch in 2008. These red-tailed hawks were resistant to repeated 

attempts to trap them and remained present during the entire breeding season. A red-tailed hawk was 

trapped in the Seasonal Pond area and was relocated. 

The gull-billed tern (Gelochilodon nilotica) has increased its nesting presence near least tern and 

snowy plover nesting areas of San Diego County. This tern is a threat to least tern and snowy plover 

chicks. On 3 occasions gull-billed terns were present during the 2008-breeding season at Bolsa 

Chica. These sightings were in the Seasonal Pond area (Cells 19 and 11) and NS1. There is no 

evidence to suggest that either least tern or plover chicks were depredated. The gull-billed tern visits 

were of no more than 2 or 3 days each. 

Chick loss to black skimmers is believed to be significant on NS1. The only other potential predators 

regularly seen on NS1 were gulls. Other breeding birds on NS1, elegant, royal and Caspian terns, 

were not probable predators. 



Black-crowned night herons, Cooper’s hawk, and peregrine falcon present during all or part of the 

breeding season were not suspected predators in 2008. Management action was taken against blackcrowned 

night herons in the area of STI early in the season based upon 2007 problems with the 

species. 

No instance of predation or disease mortality of adult snowy plovers was detected in 2008. 

Table 3. Bolsa Chica Predator Removal Summary 1997-2008 

Potential 

Predator 

2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 

American 

Crow 

12 10 - 15 99 118 52 80 91 27 1 2 

America 

Kestrel 

4 4 6 13 19 5 12 13 15 46 14 2 

Loggerhead 

Shrike 

- - 4 1 10 5 3 6 2 5 - - 

Common 

Raven 

- 4 2 1 2 4 5 6 3 2 - - 

Cooper’s 

Hawk 

1 - - 8 - - - - - - - - 

Peregrine 

Falcon 

- 1 - - - - - - - - - - 

Red-tailed 

Hawk 

1 - - - - - - - - - - - 

Gulls 1 7 - 1 - - - - - - - - 

Skunk - - - - 2 1 - - - - - - 

Coyote - - - - - - - - - - - - 

Weasel - - - - - - - - - - - - 

Ground 

3 unkn* unkn* unkn* unkn* unkn* - - - - - - 

Squirrel 

* bait stations used, therefore the number removed is unknown (unkn). 

MANAGEMENT RECOMMENDATIONS 

The 2008 western snowy plover breeding season resulted in excellent nest survival rates. The high 

nest survival rates are attributable to management actions such as the use of MEs. The fledgling rate 

(Table 2) was also higher than in 2007, ranging from 57 to 109 fledglings. Therefore, management 

recommendations focus on maintaining existing management actions as well as taking additional 

steps that focus on improving fledgling success. The endangered California least tern, which nests in 

the same locations as the western snowy plover, needs to be considered in all management efforts. 

The following five recommendations are proposed for upcoming nesting seasons: 

1. Continue utilizing the MEs and taking other preventive measures to protect nests 

from predation. 



The deployment of MEs on every nest has been very effective at preventing egg loss to corvids and 

coyotes. Mimic aversion nests, stocked with bitter tasting eggs, appear to have ended egg predation 

by coyotes, just as bait stations, when required, have deterred ground squirrel depredation. The 

removal of iceplant has also deterred ground squirrel depredation. These management efforts should 

continue. 

2. Develop methods to manage overcrowding on NS1. 

There are currently 7 species nesting on NS1 including American avocet, California least tern, black 

skimmer, elegant tern, royal tern, Caspian tern, as well as the western snowy plover. All species, 

except the snowy plover, are colonial nesters and nest in large groups. This high density nesting 

probably benefits all species by deterring predators from entering the site. However, mortality 

increases due to trampling of nests and chicks of the smaller species: California least terns and snowy 

plovers. Nest trampling has been observed at California least tern nests while snowy plovers have 

had the protection of the ME covering their nest. Once the eggs hatch the snowy plover chicks are 

highly mobile, leaving the security of the ME and venturing through the colonial nests to reach the 

shoreline and risking the possibility of trampling and aggressive behavior from the colonial nesters. 

In these overcrowded conditions, monitoring on NS1, in the same manner that has been utilized in 

the past, may no longer be possible after the elegant terns, Caspian terns, and black skimmers start 

nesting. In 2008, all nest monitoring on this site had to be halted in July due to the density of birds 

and the potential threat that any disturbance may cause to nests and chicks. 

This problem requires long-term management that would address overcrowding and its effect on 

listed species, particularly the snowy plover, as well as a review of monitoring methods that can be 

safely utilized in the future. Management decisions could include: 1) Allowing the terns, skimmers, 

and plovers to continue nesting and abandon monitoring the listed species for reproductive success in 

the manner utilized in the past. New methods of estimating success would need to be adopted; 2) 

Encourage some of the species to utilize NS2 and NS3 (see management recommendation 4. 3) 

Actively discourage the elegant tern and black skimmer from nesting on NS1 in hopes that they will 

return to NTI. 4) Continue the use of decoys to attract elegant tern to NTI and acquire black 

skimmer decoys to attract skimmers to NTI where they have nested in the past. 

Observations of interactions between the species would be highly beneficial prior to making these 

decisions. Although the California least tern and western snowy plover are listed species, the black 

skimmer is a CDFG Species of Special Concern, and the elegant, royal, and Caspian tern have 

limited areas for breeding. Utilizing a blind for regular observations, during the nesting season, 

could give management insight on the negative effects and/or benefits of this high-density nesting. 

3. Improve water management in the Seasonal Ponds 

A number of cells (i.e. Cell 11, 13, and 32) within the Seasonal Ponds were not available in 2008 for 

nesting due to flooding. These ponds normally flood during the winter but dry out prior to the snowy 

plover nesting season. In 2008 water was not able to drain into Freeman Creek due to elevated levels 

in the creek. Cell 11, in particular, has been highly used for snowy plover nesting in the past years 

but was not available in 2008. This flooding caused the snowy plover to expand into potentially less 

suitable cells as well as the roadways in order to locate suitable, dry nesting areas. Nesting in the 

Seasonal Ponds has decreased over the last 3 years, probably due to the creation of NS1 (Appendix 



2); therefore, increasing the number of cells available in the Seasonal Ponds would also provide 

increased potential for nesting opportunities. 

Based on conditions in the Full Tidal Basin, it is likely that similar pond basin flooding will recur in 

future years and that an active water management strategy will be necessary to draw down water in 

the late winter months. A water management plan must be completed to develop triggers for 

seasonal water level reduction to accommodate ground-nesting birds on the dry pond basin floors. 

4. Increase usage and reproductive success on NS2 and NS3. 

NS2 has been utilized only one time (2007) for nesting by snowy plovers and no terns have used it. 

NS3 had 5 snowy plover nests in 2008 with a modest 0.6 fledge rate. No other species have utilized 

these nest sites. These are both large nesting sites that could be utilized by snowy plover or one or 

more of the tern species to alleviate the high nesting pressure on NS1. If these sites are to be utilized 

by snowy plover they require maintenance to make them more attractive. 1) Vegetation, on both 

sites, is required to help aid in shelter and enhance foraging. This could be accomplished in the same 

manner as NS1, by watering the site during the winter months to encourage growth on the existing 

seed bank. 2) NS2 does not appear to be very attractive to the snowy plover. The slopes are very 

steep and there is no vegetation even along the channel that surrounds the nest site, where the chicks 

would be required to forage. This channel goes all the way around the nest site. Consideration 

should be given to enhancing this site for snowy plover nesting or managing it for one or more of the 

nesting tern species. 

5. Develop methods to increase shelter and forage opportunities for snowy plover 

chicks on NS1. 

Recommendations were made in the 2007 snowy plover report on increasing shelter and forage 

opportunities for snowy plovers on NS1. Many of these recommendations were implemented and 

probably increased the chicks’ survival. These actions included increasing native vegetation by 

watering the site during the winter months, removing non-natives with herbicides and by hand, and 

putting out tiles for the chicks to hide under. The tiles provided protection from both predation and 

trampling. 

These measures have enhanced the nest site; however, the snowy plover chicks are more likely to be 

foraging along the shoreline. Wrack does not appear to be accumulating along the shoreline and 

efforts to move ocean debris to the area are quickly washed away with the tide. A variety of 

approaches could be implemented, perhaps initially on a small scale, to determine the best way to 

enhance the structure and foraging opportunities in this area. Wrack placed along the shoreline could 

be anchored at the high tide line to prevent it from washing out with the tide. Pickleweed is 

beginning to grow along the high tide line. This should be encouraged and perhaps enhanced 

through further plantings. Another possibility is to artificially enhance the structure of the shoreline 

by permanently anchoring logs or large rocks along a portion of the shoreline. These permanent 

structures will, quite likely, cause some areas to erode and others to accumulate sand and debris. The 

benefits of these structures should 1) act as a shelter for chicks to hide; 2) provide a way of retaining 

some of the natural debris; 3) change the dynamics of broods by providing barriers between 

established foraging territories. 



Ongoing and adaptive management actions are essential to improving western snowy plover 

reproductive success at Bolsa Chica, which provides the best nesting option for snowy plovers within 

a 60-mile radius. 

ACKNOWLEDGMENTS 

We offer special thanks to Wally Ross who performed the predator management actions that are so 

important to snowy plover reproductive success at Bolsa Chica. 



LITERATURE CITED 

Fancher, J. 1998. Western snowy plover nesting at Bolsa Chica, Orange County, California. 1997. A 

report of the Fish and Wildlife Service, Carlsbad Office. April 1998. 22pp. 

Fancher, J., R. Zembal, L. Hays, and P. Knapp. 1998. Western snowy plover nesting at Bolsa Chica, 

Orange County, California. 1998. A report of the Fish and Wildlife Service, Carlsbad Office. 

October 1998. 27pp. 


County, California 1999 and 2000. A report of the Fish and Wildlife Service, Carlsbad 

Office. February 2001. 34pp 


County, California 2001. A report of the Fish and Wildlife Service, Carlsbad Office. 

February 2002. 24pp 



December 2002. 23pp 


County, California 2003. A report of the Fish and Wildlife Service, Carlsbad Office. January 

2004 22pp 

Fancher, J, P. Knapp, and L. Hays. 2005. Western snowy plover nesting at Bolsa Chica, Orange 

County, California 2004. A report of the Fish and Wildlife Service, Carlsbad Office. January 

2005 25pp 



December 2005 28pp 



February 2007 28pp 

Federal Register. 1993. Endangered and threatened wildlife and plants; determination of threatened 

status of the Pacific Coast population of the western snowy plover. Federal Register 58: 

12864-12874. 

Gochfield M. and J. Burger 1994. Black Skimmer (Rynchops niger). In The Birds of North America, 

No. 108 (A. Poole and F. Gills, Eds.) Philadelphia: The academy of Natural Sciences; 

Washingon, D.C.: The American Ornighologists’ Union. 

Knapp, P., B. Peterson and J. Fancher. 2007. Western snowy plover nesting at Bolsa Chica, Orange 


December 2007 22pp 



Page, G. W., J. S. Warriner, J.C. Warriner, and P.W. Patton 1995. Snowy Polver (Charadrius 

alexandrinus) in The Birds of North America (A. Poole and F. Gill, eds.) No. 154. Acad. Nat. 

Sci. Philadelphia 

Ross, W.L. 1999. Bolsa Chica wetlands 1999 breeding season predator management report. A report 

for the Fish and Wildlife Service. 3pp. 

Ross, W.L. 2000. Bolsa Chica wetlands California least tern, western snowy plover, 2000 breeding 

season predator management report. A report for the Fish and Wildlife Service. 10pp. 


season predator management report. A report for the Fish and Wildlife Service. 9 pp. 













Tucker, M. A. and A. N. Powell. 1999. Snowy Plover diets in 1995 at a Coastal Southern California 

Breeding Site. Western Birds 30: 44-48. 

U.S. Fish and Wildlife Service. 2007. Recovery Plan for the Pacific Coast Population of the Western 

Snowy Plover (Charadrius alexandrinus nivosus). In 2 volumes. Sacramento, California. xiv 

+ 751 pages. 

U.S. Fish and Wildlife Service. 2001a. Formal section 7 Biological Opinion on the Bolsa Chica 

Lowland Restoration Project, Orange County, California (FWS No. 1-66-01-1653). April 16, 

2001. 22pp with attachment. 

U.S. Fish and Wildlife Service, Corps of Engineers, and State Lands Commission. 2001. Final 

environmental impact report/environmental impact statement for the Bolsa Chica Lowlands 

Restoration Project. April 2001. Appendices A-H and Volumes I-VI. 



Appendix 1. Snowy plover eggs laid, chicks hatched, and fledged at Bolsa Chica, 2008 

Nest # Cell # date found date ended eggs nest fate chicks fledglings 

1 STI 3-17 4-22 3 H 3 0 

2 NS1 BB2 3-21 4-18 3 H 3 3 

3 NS1 V1 3-26 4-28 3 2H1A 2 -- 

4 22 3-28 3-28 1 P 0 0 

5 NS1 H1 3-28 4-25 3 H 3 1 

6 NS1 E1 3-28 4-28 3 H 3 3 

7 22 3-28 5-02 3 H 3 1 

8 NS1 Z2 3-28 4-30 3 H 3 1 

9 NS1 O1 3-29 4-25 3 H 3 -- 

10 NS1 L2 3-30 4-23 3 2H1A 2 1 

11 NS1 I1 4-02 5-01 3 2H1A 2 -- 

12 STI K3/4 4-02 4-29 3 H 3 0 

13 NS3 6D 4-05 5-07 3 H 3 3 

14 NS1 K1 4-05 5-12 3 H 3 -- 

15 10 4-07 5-12 3 H 3 1 

16 NS3 5C 4-08 5-06 3 H 3 0 

17 NS1 V2 4-10 5-06 3 H 3 -- 

18 NS1 F2 4-15 5-18 2 H 2 -- 

19 STI 4-17 5-06 2 A 0 0 

20 NTI 4-17 5-04 3 A 0 0 

21 NS1 D1 4-18 4-19 1 P 0 0 

22 22 4-18 5-17 3 H 3 0 

23 NS1AA2 4-21 5-15 3 H 3 2 

24 NS1 W1 4-21 5-17 3 2H 1A 2 -- 

25 NS3 3C 4-23 5-25 3 H/P 3 0 

26 NS1 M1 5-01 6-08 3 H 3 -- 




27 10 5-05 6-07 3 2H1A 2 0 

28 NS1H1/2 5-07 5-22 3 H 3 -- 

29 STI 5-07 6-08 3 H 3 3 

30 22 5-12 6-10 3 H 3 0 

31 NS1 J2 5-12 6-04 3 2H1A 2 -- 

32 NS1 R1 5-12 5-26 3 H 3 -- 

33 NS1 02 5-13 5-26 3 H 3 -- 

34 NS1 Q2 5-13 6-01 3 H 3 1 

35 NS1 J1 5-14 6-03 3 H 3 -- 

36 NS1 T1 5-14 6-10 3 H 3 -- 

37 RD 9/10 5-14 6-14 3 2H1A 2 0 

38 RD 10/2 5-17 6-17 3 H 3 3 

39 NS1J1/2 5-19 6-19 3 H 3 -- 

40 NS1M1 5-19 6-19 3 2H1A 2 -- 

41 9 5-20 6-15 3 H 3 3 

42 12 5-20 6-16 3 H 3 3 

43 NS1 X1 5-21 6-13 3 H 3 2 

44 NS1 Y2 5-26 6-24 3 H 3 2 

45 NS3 B3 6-1 6-29 3 2H1A 2 -- 

46 12 6-2 6-30 3 H 3 3 

47 NS1 W1 6-5 7-01 3 H 3 -- 

48 NS1 H1 6-5 6-30 3 H 3 -- 

49 NS1 O1 6-5 7-01 3 H 3 -- 

50 NS1 G1 6-7 6-30 3 H 3 0 

51 NS1AA2 6-7 7-2 3 H 3 1 

52 NS1 E2 6-8 7-9 3 H 3 0 

53 22 6-12 7-12 3 H 3 0 




54 NS1 Y1 6-12 6-29 3 H 3 0 

55 NS3 6-25 7-19 3 H 3 0 

56 10 6-25 7-15 3 H 3 0 

57 NS1 Y2 6-25 7-15 3 H 3 0 

58 NS1AA2 6-25 6-30 3 H 3 1 

59 NS1 J1 6-26 7-25 3 H 3 0 

60 NS1 K1 6-26 7-25 3 2H1A 2 -- 

61 19 6-28 7-25 3 H 3 0 

62 12 6-28 7-27 2 H 2 0 

63 RD10/2 7-13 8-2 3 H 3 0 

64 19 7-16 8-9 3 H 3 1 

65 19 7-16 8-15 2 A 0 0 

66 19 7-16 8-6 3 H 3 2 

67 22 7-16 8-2 3 H 3 1 

2008 Season Totals 193 

eggs 

2P, 3A, 62H 

67 Nests 

174 

chicks 

45++ 

fledglings 

P = predated; A = abandoned; H – hatched 

Note: In the Nest Fate column, 2H1A means the nest hatched but only two eggs produced chicks, one egg was 

abandoned. 


Western Snowy Plover Nesting at Bolsa Chica, 2008 December 2008 

Appendix 2. Distribution of Western Snowy Plover Nests at Bolsa Chica for 1997 through 2008. 

Distribution of nests 

Year 

Total # 

Nests Cell 1 Cell 3 Cell 4 Cell 5 Cell 6 Cell 8 Cell 59 Cell 44 Cell 62 FTB NTI NS1 NS2 NS3 Total 

1997 31 5 1 4 3 1 14 

1998 34 7 5 1 1 2 16 

1999 38 2 9 1 1 1 14 

2000 39 1 9 1 11 

2001 55 1 1 11 4 1 1 19 

2002 50 8 3 1 1 1 14 

2003 32 1 8 1 1 11 

2004 65 6 9 1 1 17 

2005 51 1 5 6 

2006 71 13 15 2 8 38 

2007 50 19 8 27 

2008 67 1 37 5 43 

Cells that were no longer available after 2005 

Cells only available after 2005 

Year Cell 2 Cell 9 Cell 10 Cell 11 Cell 12 Cell 13 Cell 14 Cell 17 Cell 18 Cell 19 Cell 22 Cell 30 Cell 32 Cell 33 Cell 34 Cell 36 STI Total 

1997 4 7 1 1 2 2 17 

1998 2 7 6 1 1 1 18 

1999 6 5 1 1 5 4 2 24 

2000 2 6 12 1 1 1 1 3 1 28 

2001 1 8 11 9 5 2 36 

2002 1 2 1 10 3 3 5 10 1 36 

2003 6 1 2 2 1 9 21 

2004 5 12 13 2 1 1 3 1 4 1 5 48 

2005 1 6 8 12 3 1 4 3 7 45 

2006 2 6 5 13 2 1 4 33 

2007 1 6 3 1 3 4 1 4 23 

2008 2 5 3 4 6 4 24 




APPENDIX 2-A. MONTHLY TIDE PLOTS 2008 



Monthly tidal elevations for the Bolsa Chica Wetlands Full Tidal Basin (Tide) and Los Angeles Outer Harbor (LA) for January 2008. Elevations are in ft NAVD. 

8.00 

6.00 

4.00 

2.00 

0.00 

-2.00 


Tide (ft-NAVD) 

LA (ft-NAVD) 



Monthly tidal elevations for the Bolsa Chica Wetlands Full Tidal Basin (Tide) and Los Angeles Outer Harbor (LA) for February 2008. Elevations are in feet NAVD. 

8.00 

6.00 

4.00 

2.00 

0.00 

-2.00 

-4.00 

February 2008 


LA (ft-NAVD) 



Monthly tidal elevations for the Bolsa Chica Wetlands Full Tidal Basin (Tide) and Los Angeles Outer Harbor (LA) for March 2008. Elevations are in feet NAVD. 

6.00 

5.00 

4.00 

3.00 

2.00 

1.00 

0.00 

-1.00 

-2.00 

March 2008 


LA (ft-NAVD) 



Monthly tidal elevations for the Bolsa Chica Wetlands Full Tidal Basin (Tide) and Los Angeles Outer Harbor (LA) for April 2008. Elevations are in feet NAVD. 

8.00 

6.00 

4.00 

2.00 

0.00 

-2.00 



LA (ft-NAVD) 



Monthly tidal elevations for the Bolsa Chica Wetlands Full Tidal Basin (Tide) and Los Angeles Outer Harbor (LA) for May 2008. Elevations are in feet NAVD. 

8.00 

6.00 

4.00 

2.00 

0.00 

-2.00 

-4.00 

May 2008 


LA (ft-NAVD) 



Monthly tidal elevations for the Bolsa Chica Wetlands Full Tidal Basin (Tide) and Los Angeles Outer Harbor (LA) for June 2008. Elevations are in feet NAVD. 

8.00 

6.00 

4.00 

2.00 

0.00 

-2.00 

-4.00 

June 2008 


LA (ft-NAVD) 



Monthly tidal elevations for the Bolsa Chica Wetlands Full Tidal Basin (Tide) and Los Angeles Outer Harbor (LA) for July 2008. Elevations are in feet NAVD. 

8.00 

6.00 

4.00 

2.00 

0.00 

-2.00 

-4.00 



LA (ft-NAVD) 



Monthly tidal elevations for the Bolsa Chica Wetlands Full Tidal Basin (Tide) and Los Angeles Outer Harbor (LA) for August 2008. Elevations are in feet NAVD. 

8.00 

6.00 

4.00 

2.00 

0.00 

-2.00 

August 2008 


LA (ft-NAVD) 



Monthly tidal elevations for the Bolsa Chica Wetlands Full Tidal Basin (Tide) and Los Angeles Outer Harbor (LA) for September 2008. Elevations are in feet NAVD. 

8.00 

6.00 

4.00 

2.00 

0.00 

-2.00 

September 2008 


LA (ft-NAVD) 



Monthly tidal elevations for the Bolsa Chica Wetlands Full Tidal Basin (Tide) and Los Angeles Outer Harbor (LA) for October 2008. Elevations are in feet NAVD. 

8.00 

6.00 

4.00 

2.00 

0.00 

-2.00 



LA (ft-NAVD) 



Monthly tidal elevations for the Bolsa Chica Wetlands Full Tidal Basin (Tide) and Los Angeles Outer Harbor (LA) for November 2008. Elevations are in feet NAVD. 

8.00 

6.00 

4.00 

2.00 

0.00 

-2.00 

November 2008 


LA (ft-NAVD) 



Monthly tidal elevations for the Bolsa Chica Wetlands Full Tidal Basin (Tide) and Los Angeles Outer Harbor (LA) for December 2008. Elevations are in feet NAVD. 

8.00 

6.00 

4.00 

2.00 

0.00 

-2.00 



LA (ft-NAVD) 




APPENDIX 2-B. BOLSA BEACH PROFILE PLOTS 














































APPENDIX 2-C. MSL BEACH WIDTH 




Mean Sea Level Beach Width (4) (m) 

Survey 


Date 249+30 311+22 318+30 333+30 350+71 378+29 423+89 

May 1963 36.6 (1) 17.7 (1) 21.0 (1) 28.9 (1) 33.0 (1) 33.6 (1) 71.2 (1) 

Jul 1964 40.1 (1) 22.7 (1) 33.2 (1) 29.9 (1) - - - 

Oct 1966 48.8 (1) 24.6 (1) 33.4 (1) 30.7 (1) 35.4 (1) 22.0 (1) 58.0 (1) 

Apr 1969 63.2 (1) 34.6 (1) 47.5 (1) 40.4 (1) 40.4 (1) 25.2 (1) 43.6 (1) 

May 1973 88.6 (1) 46.4 (1) 49.0 (1) 40.1 (1) 49.0 (1) 19.2 (1) 34.5 (1) 

Dec 1978 83.3 (1) 61.6 (1) - - 37.4 (1) 29.6 (1) 55.0 (1) 

Jun 1979 113.8 (1) 74.4 (1) - - 51.9 (1) 42.3 (1) 67.6 (1) 

Apr 1982 82.5 (1) 55.3 (1) 57.3 (1) 48.9 (1) 44.2 (1) 19.5 (1) 70.3 (1) 

Jan 1983 84.0 (1) 54.4 (1) 58.4 (1) 53.4 (1) 43.6 (1) 26.2 (1) 69.5 (1) 

Feb 1992 89.3 58.3 - - 61.4 11.9 82.1 

May 1992 96.4 61.6 - - 58.3 14.3 75.1 

Nov 1992 93.5 54.1 - - 56.4 13.7 81.0 

May 1993 84.5 57.9 - - 56.1 13.0 65.5 

Oct 1993 92.6 68.0 - - 67.0 26.4 72.9 

Apr 1994 90.0 66.2 - - 62.5 30.4 76.0 

Oct 1994 100.7 69.7 - - 73.6 33.6 89.5 

May 1995 83.6 60.2 - - 54.3 19.7 69.5 

Nov 1997 93.6 (2) 88.6 (2) - - 56.1 (2) 15.7 (2) 83.6 (2) 

Mar 2002 78.1 60.2 67.3 (1) 66.0 (1) 57.7 20.7 96.4 

Oct 2005 85.9 (3) 63.4 (3) 70.5 (3) 79.3 (3) 62.1 (3) 36.1 (3) 120.2 (3) 

Mar 2006 71.2 (3) 64.6 (3) 64.1 (3) 67.5 (3) 53.6 (3) 22.3 (3) 111.3 (3) 

Jan 2007 86.8 70.3 85.9 66.6 54.1 23.9 110.5 

May 2007 84.7 76.2 86.1 61.9 48.9 27.8 106.9 

Oct 2007 91.0 85.5 82.7 72.3 54.8 41.1 113.3 

May 2008 74.5 86.3 93.5 46.8 42.6 21.3 108.8 

Oct 2008 87.1 87.1 93.5 80.5 57.2 26.4 106.6 

Notes: 

(1) Beach profile data generated from TIN model 

(2) Beach profile data interpolated at 15.24 m (50.0 ft) intervals 

(3) Beach profile data generated from LIDAR with a TIN model, topography only 

(4) Mean Sea Level (MSL) lies 0.79 m above NAVD88 datum 
























2007 Annual Report 

APPENDIX 2-D. SEDIMENT VOLUME DATA 




Subaerial Volume (4) (m 3 /m) 

Survey 


Date 249+30 311+22 318+30 333+30 350+71 378+29 423+89 

May 1963 40 (1) 28 (1) 50 (1) 64 (1) 33 (1) 35 (1) 165 (1) 

Jul 1964 45 (1) 26 (1) 82 (1) 74 (1) - - - 

Oct 1966 80 (1) 18 (1) 69 (1) 55 (1) 30 (1) 19 (1) 128 (1) 

Apr 1969 131 (1) 66 (1) 114 (1) 87 (1) 43 (1) 10 (1) 80 (1) 

May 1973 231 (1) 111 (1) 147 (1) 103 (1) 90 (1) 10 (1) 68 (1) 

Dec 1978 206 (1) 138 (1) - - 69 (1) 68 (1) 96 (1) 

Jun 1979 209 (1) 146 (1) - - 96 (1) 24 (1) 131 (1) 

Apr 1982 217 (1) 151 (1) 179 (1) 139 (1) 77 (1) 12 (1) 189 (1) 

Jan 1983 227 (1) 137 (1) 179 (1) 140 (1) 72 (1) 20 (1) 156 (1) 

Feb 1992 246 153 - - 116 1 214 

May 1992 259 148 - - 107 3 217 

Nov 1992 262 142 - - 104 1 224 

May 1993 246 151 - - 110 1 195 

Oct 1993 245 153 - - 119 9 198 

Apr 1994 253 170 - - 113 10 212 

Oct 1994 250 173 - - 124 14 219 

May 1995 244 155 - - 107 7 194 

Nov 1997 233 (2) 294 (2) - - 98 (2) 2 (2) 220 (2) 

Mar 2002 206 181 217 (1) 211 (1) 130 11 277 

Oct 2005 214 (3) 173 (3) 199 (3) 221 (3) 100 (3) 30 (3) 326 (3) 

Mar 2006 200 (3) 172 (3) 200 (3) 241 (3) 113 (3) 9 (3) 346 (3) 

Jan 2007 226 211 268 257 113 16 343 

May 2007 237 221 276 234 101 21 338 

Oct 2007 252 235 264 232 97 38 361 

May 2008 214 259 311 186 81 12 342 

Oct 2008 233 258 305 210 84 12 341 

Notes: 



(3) Beach profile data generated from LIDAR with a TIN model, topography only 

(4) 

Subaerial volume boundary extends from the back beach to the intersection of the 

beach profile and Mean Sea Level (MSL). MSL lies 0.79 m above NAVD88 datum 




Transect 249+30 

400 

350 

Stage 1 Stage 4 

Stage 7 Stage 8 Stage 9 Stage 10 Stage 11 

3.1 mil m 3 1.7 mil m 3 1.3 mil m 3 2.0 mil m 3 1.4 mil m 3 1.2 mil m 3 1.7 mil m 3 

Subaerial Volume (m 3 /m) 

300 

250 

200 

150 

100 

50 

0 

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 

Year 

= Surfside-Sunset Nourishment 





400 

350 





300 

250 

200 

150 

100 

50 

0 

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 

Year 






400 

350 





300 

250 

200 

150 

100 

50 

0 

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 

Year 






400 

350 





300 

250 

200 

150 

100 

50 

0 

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 

Year 






400 

350 





300 

250 

200 

150 

100 

50 

0 

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 

Year 






400 

350 





300 

250 

200 

150 

100 

50 


0 

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 

Year 





400 

350 





300 

250 

200 

150 

100 

50 

0 

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 

Year 





Shorezone Volume (3) (m 3 /m) 

Survey 


Date 249+30 311+22 318+30 333+30 350+71 378+29 423+89 

May 1963 4901 (1) 7556 (1) 7069 (1) 6577 (1) 5191 (1) 3990 (1) 5661 (1) 

Jul 1964 5166 (1) 7605 (1) 7342 (1) 6848 (1) - - - 

Oct 1966 4973 (1) 7449 (1) 7182 (1) 6757 (1) 5247 (1) 4162 (1) 5637 (1) 

Apr 1969 4991 (1) 7384 (1) 7087 (1) 6700 (1) 5530 (1) 4180 (1) 5431 (1) 

May 1973 5324 (1) 7713 (1) 7324 (1) 6798 (1) 5246 (1) 4068 (1) 5374 (1) 

Dec 1978 5398 (1) 8067 (1) - - 5388 (1) 4073 (1) 5497 (1) 

Jun 1979 5411 (1) 7752 (1) - - 5314 (1) 4107 (1) 5448 (1) 

Apr 1982 5313 (1) 7390 (1) 7051 (1) 6575 (1) 5079 (1) 4021 (1) 5538 (1) 

Jan 1983 5417 (1) 7686 (1) 7408 (1) 6923 (1) 5355 (1) 4061 (1) 5656 (1) 

Feb 1992 5385 7293 - - 5231 3697 5528 

May 1992 5385 7352 - - 5183 3783 5581 

Nov 1992 5378 7384 - - 5289 3890 5570 

May 1993 5428 7669 - - 5348 3857 5655 

Oct 1993 5397 7694 - - 5373 4197 5710 

Apr 1994 5452 7701 - - 5438 4083 5785 

Oct 1994 5400 7388 - - 5416 4114 5812 

May 1995 5439 7630 - - 5376 3925 5772 

Nov 1997 5437 (2) 7848 (2) - - 5474 (2) 3948 (2) 5886 (2) 

Mar 2002 5375 7635 7310 (1) 6873 (1) 5323 3937 6022 

Oct 2005 - - - - - - - 

Mar 2006 - - - - - - - 

Jan 2007 5407 8369 8234 7255 5405 4068 6210 

May 2007 5381 8268 8292 7386 5433 4075 6167 

Oct 2007 5394 8327 8258 7304 5380 4119 6193 

May 2008 5347 8186 8026 7105 5285 3923 6157 


Notes: 



(3) 

Shorezone volume boundary extends from the back beach to the statistical 

range of closure. Shorezone volume basement elevation located at -13.83 m 

NAVD88 (-45.0 ft, MLLW, 1960-1978 tidal datum epoch) 




Shorezone Volume Change Relative to 1963 Survey (3) (m 3 /m) 

Survey 


Date 249+30 311+22 318+30 333+30 350+71 378+29 423+89 

May 1963 0 (1) 0 (1) 0 (1) 0 (1) 0 (1) 0 (1) 0 (1) 

Jul 1964 265 (1) 49 (1) 273 (1) 271 (1) - - - 

Oct 1966 72 (1) -107 (1) 113 (1) 180 (1) 56 (1) 172 (1) -24 (1) 

Apr 1969 90 (1) -172 (1) 18 (1) 123 (1) 339 (1) 190 (1) -230 (1) 

May 1973 423 (1) 157 (1) 255 (1) 221 (1) 55 (1) 78 (1) -287 (1) 

Dec 1978 497 (1) 511 (1) - - 197 (1) 83 (1) -164 (1) 

Jun 1979 510 (1) 196 (1) - - 123 (1) 117 (1) -213 (1) 

Apr 1982 412 (1) -166 (1) -18 (1) -2 (1) -112 (1) 31 (1) -123 (1) 

Jan 1983 516 (1) 130 (1) 339 (1) 346 (1) 164 (1) 71 (1) -5 (1) 

Feb 1992 484 -263 - - 40 -293 -133 

May 1992 484 -204 - - -8 -207 -80 

Nov 1992 477 -172 - - 98 -100 -91 

May 1993 527 113 - - 157 -133 -6 

Oct 1993 496 138 - - 182 207 49 

Apr 1994 551 145 - - 247 93 124 

Oct 1994 499 -168 - - 225 124 151 

May 1995 538 74 - - 185 -65 111 

Nov 1997 536 (2) 292 (2) - - 283 (2) -42 (2) 225 (2) 

Mar 2002 474 79 241 (1) 296 (1) 132 -53 361 

Oct 2005 - - - - - - - 

Mar 2006 - - - - - - - 

Jan 2007 506 813 1165 678 214 78 549 

May 2007 480 712 1223 809 242 85 506 

Oct 2007 493 771 1189 727 189 129 532 

May 2008 446 630 957 528 94 -67 496 


Notes: 



(3) 

Shorezone volume boundary extends from the back beach to the statistical 

range of closure. Shorezone volume basement elevation located at -13.83 m 

NAVD88 (-45.0 ft, MLLW, 1960-1978 tidal datum epoch) 





Shorezone Volume Change Relative to 1963 (m 3 /m) 

1400 

1200 

1000 

800 

600 

400 

200 

0 

-200 

-400 




1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 

Year 







1400 

1200 

1000 

800 

600 

400 

200 

0 

-200 

-400 




1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 

Year 







1400 

1200 

1000 

800 

600 

400 

200 

0 

-200 

-400 




1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 

Year 







1400 

1200 

1000 

800 

600 

400 

200 

0 

-200 

-400 




1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 

Year 







1400 

1200 

1000 

800 

600 

400 

200 

0 

-200 

-400 




1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 

Year 







1400 

1200 

1000 

800 

600 

400 

200 

0 

-200 

-400 




1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 

Year 







1400 

1200 

1000 

800 

600 

400 

200 

0 

-200 

-400 




1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 

Year 





APPENDIX 2-E. MSL BEACH WIDTH MEASUREMENTS 





MSL Beach Width/Distance to Berm (meters) 

140 

120 

100 

80 

60 

40 

20 

Distance to Berm 

MSL Beach Width 


From Profile Data 

0 

2007 2008 2009 

Date 






140 

120 

100 

80 

60 

40 

20 





0 

2007 2008 2009 

Date 






140 

120 

100 

80 

60 

40 

20 





0 

2007 2008 2009 

Date 






140 

120 

100 

80 

60 

40 

20 





0 

2007 2008 2009 

Date 






140 

120 

100 

80 

60 

40 

20 





0 

2007 2008 2009 

Date 






140 

120 

100 

80 

60 

40 

20 





0 

2007 2008 2009 

Date 





140 


120 

100 

80 

60 

40 

20 

0 

2007 2008 2009 

Date 








APPENDIX 2-F. US ARMY CORPS BEACH WIDTH MEASUREMENTS 





120 

Stage 7 



1.3 mil m 3 2.0 mil m 3 1.4 mil m 3 1.2 mil m 3 1.7 mil m 3 

100 

Berm Width (meters) 

80 

60 

40 

20 

0 

1975 1980 1985 1990 1995 2000 2005 2010 

Year 






120 

Stage 7 

Stage 8 

Stage 9 



100 


80 

60 

40 

20 

0 

1975 1980 1985 1990 1995 2000 2005 2010 

Year 






120 

Stage 7 

Stage 8 

Stage 9 



100 


80 

60 

40 

20 

0 

1975 1980 1985 1990 1995 2000 2005 2010 

Year

2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...

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