Lake Pocotopaug Lake and Watershed Restoration Evaluation ...

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this point, but as a rough guide, an expense of $3000 to $5000 per acre served is offered. If theentire developed area of the watershed was treated in this manner, the cost could be as high as$2.7 million, but a much smaller area is more likely to be addressed by infiltration technologies.Low areas and places with soils of lower permeability, such as the immediate area around thelake and substantial additional lands just west and north of the lake, will not be appropriatecandidates for infiltration. Where possible, detention and some form of wetland treatment wouldbe most desirable for these areas. This may be possible in conjunction with existing structuresin some areas, but will be limited in already developed areas close to the lake with high groundwater table. There simply is not enough room to work and existing storm water drainagesystems route water away from roads and property for public safety purposes.Where space is adequate, the detention and wetland treatment area should be about 5% of thearea served. In other words, a 10-acre area will require a 0.5-acre detention/wetland area to betruly effective. Smaller areas will still provide some benefit, and could be enhanced withsuperior design (e.g., filter berm outlets, baffled flow), but the larger the area the better.Excluding any land costs, preparation of a detention area will cost about $100,000 per acre,each of which can handle the runoff from about 20 acres. If all developed land in the watershedwas managed through detention, the cost would be about $2.7 million, identical to the estimatedinfiltration cost.For those areas where surface and subsurface conditions simply do not allow use of infiltrationor detention systems as described above, consideration should be given to small-scaleengineered solutions. Leaching or deep catch basins (along roads), swales (perpendicular torunoff flow on developed properties), and “artificial infiltration systems” (StormTreat,StormDefender, etc. that handle smaller volumes of runoff in an engineered container sunk intothe ground) should be considered. Again, selection of techniques may be highly site-specific.The cost per unit area served will tend to be higher than that for infiltration or detention systems,although there is room for cost saving creativity and many such systems may be designed tohandle less than the ideal amount of runoff.13.3 In-Lake ActionsFurther alum treatment may be warranted if other areas of the lake as yet untreated turn out tobe significant sources of phosphorus. Such action would not be taken, however, until additionalstudy was completed. Treatment of another 100 to 150 acres of the lake would be expected tocost on the order of $100,000 to $200,000.Fish community adjustment is currently underway, although the stocking of walleye was notdone explicitly to reduce planktivorous panfish and increase zooplankton populations andgrazing capacity. Approximately 15,000 walleye were stocked in November 2001. It is notknown if this is an appropriate density to control panfish, and it may take a few years beforestocked walleye have any measurable impact, but further monitoring of zooplankton should beLake Pocotopaug Restoration Evaluation 128May 2002
sufficient to detect relevant changes in zooplankton community structure. Additional stockingmay be warranted, but it seems best to monitor for at least a year before taking further action,unless consultation with CT DEP Inland Fisheries staff indicates otherwise. Cost of stocking willbe proportional to the number and size of fish stocked. The cost of fingerlings is low andgenerally affordable (
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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
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Table 12 continued. 2001 Dry and We
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were identified to genus and enumer
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Table 13 continued. 2001 Phytoplank
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Figure 10. 2001 Phytoplankton Bioma
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The late summer bloom of blue-green
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Table 15. 2001 Zooplankton DensityZ
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Table 16. 2001 Zooplankton BiomassZ
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7.0 RELATIONSHIPS AND TRENDS7.1 Pre
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Figure 13. 1991-2001 Surface Water
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Figure 15. 2001 Surface and Mid-dep
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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 130 and 131: 12.0 ADDITIONAL DATA NEEDSManagemen
Page 132 and 133: 13.0 RECOMMENDED MANAGEMENT PROGRAM
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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