Lake Pocotopaug Lake and Watershed Restoration Evaluation ...

More documents

Recommendations

Info

12.0 ADDITIONAL DATA NEEDSManagement of Lake Pocotopaug and its watershed can proceed based on what we havelearned to date, but certain aspects of this system deserve further study to allow the mosteffective management to be implemented and to answer questions that remain from work doneto date. The following additional data collection tasks are recommended:12.1 In-Lake MonitoringDespite the apparent need for more watershed work, continued in-lake monitoring is needed aswell to assess continued success of the alum treatment in curtailing internal recycling and toevaluate both nutrient and algal dynamics in Lake Pocotopaug. One spring sampling (April),two summer samplings (June-September), and one fall sampling (October/November) fornutrients (total and dissolved phosphorus, ammonium, nitrate and total kjeldahl nitrogen) andT/DO profile, pH and SDT are suggested. Nutrients would be sampled near the surface andbottom on each date in two locations, including the current station 2 and a new station in thesouth portion or the lake, where wind mixing and sediment resuspension are potentiallyproblematic. A depth-integrated algal sample would also be collected on each date from eachstation (surface to 2XSDT depth), and a zooplankton sample should also be collected from eachin-lake station.12.2 Watershed Input MonitoringMore data are needed to better quantify loading from tributaries and storm drains, especially asrelates to any true first flush phenomenon and spring vs. summer inputs. We suggest targetingup to 12 locations during two storms, with sampling to include pre-storm (dry weather)conditions, the first flush, and a post-peak (waning hydrograph) period. Water quality variablesshould include total and dissolved phosphorus, ammonium, nitrate and total kjeldahl nitrogen.Flow data should be acquired if possible for each sampling as well, to allow a temporalbreakdown of loading during each storm. This sampling will allow an assessment of theimportance of early storm inputs vs. later storm and non-storm inputs, and discern any majordifferences among discharges to the lake (only limited differences are currently apparent).Sampling one storm in the spring and one in the summer will help confirm the apparent higherloading during spring. Combined with the past data, this should allow a more definitivedetermination of watershed inputs, upon which more cost-effective management plans can bebased.12.3 Additional Algal MonitoringIn addition to the seasonal in-lake sampling noted above, algae should be sampled from twolocations in the lake at surface and mid-depth and assessed for composition and relativeabundance during November and December on a biweekly basis. The presence of anypotentially toxic forms must be noted.Lake Pocotopaug Restoration Evaluation 124May 2002
12.4 Additional Investigative SamplingIn addition to the water quality sampling program above, up to 20 samples should be allocatedfor suspected contaminants as warranted by the above investigations. This investigativesampling allowance will enable investigation of any suspicious inputs or events relating to thelake.12.5 Algal AssaysThe occurrence of blooms in Lake Pocotopaug at relatively low phosphorus levels is unusual,and the ability of ambient phytoplankton (especially the assemblage dominated by Anabaenaaphanizomenoides) to grow at successively lowered nutrient levels should be investigated. Labassays using lake water, diluted lake water, and distilled water can be run to determine thegrowth potential of Lake Pocotopaug algae. These algae may still be getting some nutritionfrom the sediments as stored reserves in the resting stages before they germinate each year, ormay just be very effective at using low ambient levels of phosphorus. This effort should be ableto determine the proper target for phosphorus in Lake Pocotopaug to prevent these blooms, andwhether additional nutrient inactivation (in other parts of the lake) is necessary.12.6 Fish AssaysThe apparent stress on fish each winter can be investigated by lab assays using lake water andtest fish under controlled laboratory conditions. Assays should be run using water from the lakeor tributaries to determine if observed effects in the lake can be duplicated in the lab. Assaysshould occur in December and possibly January, at the time of known past stress. Assaysshould include water from near the bottom of the lake and any suspicious input source.Lake Pocotopaug Restoration Evaluation 125May 2002
Page 2 and 3:
LAKE POCOTOPAUGLAKE AND WATERSHEDRE
Page 4 and 5:
11.3 Prevent algal blooms from occu
Page 6 and 7:
LAYPERSON’S SYNOPSISLake Pocotopa
Page 8 and 9:
The stocking of walleye in Lake Poc
Page 10 and 11:
Lake Pocotopaug Restoration Evaluat
Page 12 and 13:
Period Covered 1988• Pollution fr
Page 14 and 15:
Recommendations included• Algacid
Page 16 and 17:
Major EventDecember 1999 - Fish kil
Page 18 and 19:
Table 5. Land Use from the CT DEP G
Page 20 and 21:
Page 22 and 23:
Figure 4. Lake Pocotopaug Bathymetr
Page 24 and 25:
Table 6. QA/QC on Water Quality Dat
Page 26 and 27:
Soils - USDA at MAGIC UCONN Geograp
Page 28 and 29:
Table 8. Water Quality Variables Me
Page 30 and 31:
Page 32 and 33:
Phytoplankton samples were collecte
Page 34 and 35:
where many measurements would have
Page 36 and 37:
Figure 7. 2001 Temperature and Diss
Page 38 and 39:
Table 10 continued. 2001 Lake Pocot
Page 40 and 41:
phytoplankton biomass (Wetzel 1983)
Page 42 and 43:
Figure 9. Annual June, July and Aug
Page 44 and 45:
elow 7:1 occurred on September 22,
Page 46 and 47:
Table 12. 2001 Dry and Wet Weather
Page 48 and 49:
Table 12 continued. 2001 Dry and We
Page 50 and 51:
Page 52 and 53:
Page 54 and 55:
Page 56 and 57:
were identified to genus and enumer
Page 58 and 59:
Table 13 continued. 2001 Phytoplank
Page 60 and 61:
Page 62 and 63:
Page 64 and 65:
Page 66 and 67:
Page 68 and 69:
Figure 10. 2001 Phytoplankton Bioma
Page 70 and 71:
The late summer bloom of blue-green
Page 72 and 73:
Table 15. 2001 Zooplankton DensityZ
Page 74 and 75:
Table 16. 2001 Zooplankton BiomassZ
Page 76 and 77:
7.0 RELATIONSHIPS AND TRENDS7.1 Pre
Page 78 and 79:
Figure 13. 1991-2001 Surface Water
Page 80 and 81: Figure 15. 2001 Surface and Mid-dep
Page 82 and 83: Figure 16. 1991-2001 Chlorophyll a
Page 84 and 85: Figure 18. 2001 Chlorophyll a vs. S
Page 86 and 87: Figure 20. 1991-2001 July and Augus
Page 88 and 89: Table 17. Empirical Model Calculati
Page 90 and 91: Table 18. Total Phosphorus Loading
Page 92 and 93: Table 19. Wet Weather Loading Summa
Page 94 and 95: With the best possible treatment of
Page 96 and 97: water quality should focus on input
Page 98 and 99: 10.0 MANAGEMENT NEEDS AND OBJECTIVE
Page 100 and 101: 11.2 Reducing Total Phosphorus and
Page 102 and 103: undeveloped forest land, an opportu
Page 104 and 105: Figure 22. Buffer Strips for Pollut
Page 106 and 107: Figure 23. Catch Basin with Sump an
Page 108 and 109: early spring to capture what appear
Page 110 and 111: Figure 26. Infiltration Systems.Lak
Page 112 and 113: Figure 27. Constructed Treatment We
Page 114 and 115: Chemical TreatmentIn-stream chemica
Page 116 and 117: TABLE 21. MANAGEMENT OPTIONS FOR CO
Page 118 and 119: TABLE 21 continued. MANAGEMENT OPTI
Page 132 and 133: 13.0 RECOMMENDED MANAGEMENT PROGRAM
Page 134 and 135: this point, but as a rough guide, a
Page 136 and 137: 14.0 REFERENCESAd Hoc Lake Advisory
Page 138 and 139: Scheuler T.R., P.A. Kumble, & M.A.
Page 140 and 141: Appendix B:Supplemental Tables and
Page 142: Appendix D:Educational MaterialsLak
show all

Lake Pocotopaug Lake and Watershed Restoration Evaluation ...

Create successful ePaper yourself

Delete template?

Save as template?