Lake Pocotopaug Lake and Watershed Restoration Evaluation ...

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10.0 MANAGEMENT NEEDS AND OBJECTIVESAlthough once used for industrial purposes, current use of Lake Pocotopaug is heavily weightedtowards recreational activities, and providing continued high quality swimming, boating andfishing experiences is the primary goal of management for this system. Achieving this goaldepends upon managing the watershed and the lake for reduced sediment and nutrient loading,less algae, and healthy fish populations.The surrounding watershed is heavily forested. However, this land is primarily privately ownedand protecting this land from development may be a difficult task. Development, realistically, isinevitable, although current environmental regulations will restrict it to some degree and willdictate some water quality safeguards. Ensuring proper storm water Best ManagementPractices (BMPs) during and after any development is essential. Unfortunately for the lake,development around the lakeshore is already dense. Reducing impacts from this area inaddition to protection of what is now undeveloped land should be the focus for management ofLake Pocotopaug and it’s watershed.Concerns expressed early in this study included low water clarity and excessive algal densities.Poor water clarity has been documented since the early 1970’s. It does not appear to be solelyinfluenced by algal density, as storm-induced solids inputs and resuspended sediment fromwithin the lake are significant sources of turbidity (and reduced clarity), but algal blooms in latesummer do severely reduce water clarity without appreciable non-algal particulate abundance.Reduced suspended solids and reduced algal density are therefore the primary objectives ofmanagement for Lake Pocotopaug. These objectives will be addressed in the subsequentsections.Lake Pocotopaug Restoration Evaluation 92May 2002
11.1 Reducing Non-Algal Turbidity11.0 POTENTIAL MANAGEMENT OPTIONSControl of non-algal turbidity requires understanding the sources and having the economicresources available. In the case of Lake Pocotopaug, the source of non-algal turbidity isunclear. Sediment loading is extensive and well documented. However, there is no significantrelationship between precipitation and in-lake turbidity. This is not to say that stormwater runoffdoes not contribute to in-lake turbidity or more importantly, to sedimentation (the infilling of thelake). What it does suggest is that an additional source may be present. Lake sediment in thesouthern portion of the lake may be entrained in the water column through wind action,distributing fine sediment throughout the lake and reducing water clarity. More data are neededto prove or disprove this theory, but observations suggest that this may be a substantial factor inlowered water clarity much of the year.If mixing is a source for decreased water clarity, management can be difficult. Changing windpatterns or mixing resistance is highly impractical. Dredging of the shallow areas to reducingmixing potential or the use of benthic barriers may help in this regard, but these measures areexpensive on a large scale and do not seem appropriate for Lake Pocotopaug at this time.Alum treatment of the southern area, avoided previously because it is not deep enough to havestrong anoxia and associated phosphorus release, may both help congeal the sediments to limitresuspension and inactivate any phosphorus that does get entrained in the water column. Thisapproach has seldom been tried, however, and is somewhat experimental.Sediment inputs should be controllable. The “Storm Water Renovation and Management Planfor Lake Pocotopaug” prepared by WMC in 1995 outlines many techniques for sediment inputreduction. The plan is provided in Appendix C for further reference. This section will notdiscuss each drainage basin and the techniques to employ, as the WMC report was fairlythorough, but it will give several options to consider for sediment reduction.Areas of concern are beaches (public or private), catch basins throughout the watershed andmajor tributaries (Christopher, Hales, Bay and O’Neill Brooks). Beaches might be provided witha vegetated buffer strip, although this is unpopular with beach goers. Alternatively, using thecoarsest possible sand for beaches will help, and covering the beach with filter fabric or settingup silt fence may be viable in the off-season. The most critical time is in the spring when thereis a high potential for runoff and beach attendance is minimal, but it may be necessary to takeaction in late autumn to ensure spring protection.Beaches are only a small part of the problem, however, and management of other watershedlands will be essential to reducing solids inputs. Most alternatives for reducing sedimentation gohand in hand with phosphorus reducing techniques (a method of controlling algae). In an effortto avoid repeating sections, reduction of sediment and phosphorus will be discussed together inthe next section.Lake Pocotopaug Restoration Evaluation 93May 2002
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LAKE POCOTOPAUGLAKE AND WATERSHEDRE
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11.3 Prevent algal blooms from occu
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LAYPERSON’S SYNOPSISLake Pocotopa
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The stocking of walleye in Lake Poc
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Lake Pocotopaug Restoration Evaluat
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Period Covered 1988• Pollution fr
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Recommendations included• Algacid
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Major EventDecember 1999 - Fish kil
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Table 5. Land Use from the CT DEP G
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Figure 4. Lake Pocotopaug Bathymetr
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Table 6. QA/QC on Water Quality Dat
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Soils - USDA at MAGIC UCONN Geograp
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Table 8. Water Quality Variables Me
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Phytoplankton samples were collecte
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where many measurements would have
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Figure 7. 2001 Temperature and Diss
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Table 10 continued. 2001 Lake Pocot
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phytoplankton biomass (Wetzel 1983)
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Figure 9. Annual June, July and Aug
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elow 7:1 occurred on September 22,
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Table 12. 2001 Dry and Wet Weather
Page 48 and 49: Table 12 continued. 2001 Dry and We
Page 56 and 57: were identified to genus and enumer
Page 58 and 59: Table 13 continued. 2001 Phytoplank
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 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 130 and 131: 12.0 ADDITIONAL DATA NEEDSManagemen
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
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