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

Bolsa Chica Lowlands Restoration Monitoring
2008 Annual Report
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
Merkel & Associates, Inc. 4