The goal of the Clean Water Act (cwa) is to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters
WMA water withdrawal Summary (APPENDIX E, TABLE E5)
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WMA water withdrawal Summary (APPENDIX E, TABLE E5)
*System-wide withdrawal, all sources are not necessarily within this segment; however, Cohasset Water Department reported no water was drawn from the groundwater wells between 2000 and 2002 - all water was withdrawn from Lily Pond (MassDEP 2003c). Use AssessmentAquatic LifeHabitat and FlowDenil-type fishways have been installed at the Aaron River Reservoir Dam and the Beechwood Street Dam. Both of these fishways are reported to be in excellent condition (Reback et al. 2004). There is a flow control structure at the upstream side of Beechwood Street, Cohasset. When the boards at this flow control structure are raised (part of the public water supply system operations), the flow of Aaron River diverts into Herring Brook and into Lily Pond. The poorly designed, deteriorating notched weir-pool fish ladder at Hunters Pond is impassable (Reback et al. 2004). BiologyDense growth of the non-native aquatic macrophyte Cabomba caroliniana was observed in the Aaron River upstream from the Beechwood Street Dam (MassDEP 2001a). Chemistry – waterIn 2001 DWM conducted water quality sampling at one station (AR101) on Aaron River upstream from the outlet control structure at Beechwood Street, Cohasset (Appendix A). In-situ measurements of DO, % DO saturation, temperature, pH, conductivity, and TDS were recorded on seven occasions from June to October. Samples were collected on five occasions for total phosphorus, ammonia-nitrogen, nitrate-nitrite nitrogen, chloride, alkalinity, and hardness. The results are summarized below. Dissolved oxygen and percent saturation DO measurements by DWM ranged from 2.0 to 5.9 mg/L with the percent saturation ranging from 24 to 56%. Only one of six measurements did not meet the water quality standard of 5.0 mg/L. Temperature Temperature measurements ranged from 13.9ºC in October to 28.0ºC in June. pH, alkalinity and hardness pH was low ranging from 5.5 to 6.1 SU as were alkalinities (4 to 7 mg/L) and hardness (14 to 18 mg/L). Conductivity Specific conductance measurements ranged from 119 to 130 µS/cm. Total dissolved solids TDS measurements ranged from 76.1 to 83.3 mg/L. Nutrients Total phosphorus concentrations ranged from 0.031 to 0.059 mg/L. Ammonia-nitrogen concentrations were <0.02 mg/L for all unqualified samples and nitrate-nitrite nitrogen concentrations ranged from <0.06 to 0.08 mg/L. The Aquatic Life Use is assessed as impaired for the entire length of this segment of the Aaron River based on the presence of the barrier to anadromous fish migration and the presence of a dense infestation of a non-native macrophyte species (Cabomba caroliniana), which compromises the native, naturally diverse community of aquatic flora in the lower 0.2 mile reach of this segment (downstream from the confluence with Herring Brook). The low DO/saturation, pH, alkalinity, and hardness conditions are considered to be naturally-occurring given the large amount of upstream wetland areas. Flow alterations from the water supply diversion may affect some of these water quality conditions and are also of concern. Primary and Secondary Contact RECREATION and aestheticsIn 2001 DWM conducted bacteria sampling at one station (AR101) on Aaron River upstream from the flow control structure at Beechwood Street, Cohasset, on three occasions during the primary contact season and on one additional date, 24 October 2001 (Appendix A). Samples were analyzed for fecal coliform, E. coli and Enterococcus sp. None of the fecal coliform bacteria counts exceeded 170 cfu/100 ml. Although DWM field survey crews noted no objectionable odors or oils, dense growths of aquatic vegetation, including the non-native aquatic macrophyte Cabomba caroliniana, and algal mats were observed in the brook upstream from the flow control structure throughout the summer of 2001 (MassDEP 2001a). During one sampling occasion after significant rain, the water was described as being brownish and very turbid. Usually the water was slightly tea-stained. Although fecal coliform bacteria counts were low, the Recreational and Aesthetics uses are not assessed for the upper 0.8-mile reach of this segment of the Aaron River but are identified with an Alert Status because of the high potential for being heavily infested with a non-native aquatic macrophyte. These uses are assessed as impaired downstream from the confluence with Herring Brook because of the overabundant growth of a non-native aquatic macrophyte and the presence of algal mats frequently noted near the flow control structure. Turbidity associated with wet weather conditions is also of concern. Aaron River (MA94-28) Use Summary Table
*Alert Status issues identified, see details in use assessment recommendations The fishway at Hunters Pond should be redesigned and replaced (Reback et al. 2004). Further investigate/define the extent of the infestation of Cabomba caroliniana. In order to maintain the integrity of aquatic life in this segment of the Aaron River flow regimes should be maintained as close to a natural regime as possible (i.e., the flashboards near Beechwood Street should be used as little as possible to reverse the flow of Aaron River and Herring Brook back into Lily Pond). If changes are implemented monitoring designed to document changes in water quality conditions should be conducted. Herring Brook (Segment MA94-29) Location: Outlet Lily Pond, Cohasset to confluence with Aaron River, Cohasset. Segment Length: 0.3 miles Classification: Class A Land-use estimates (top 3, excluding water) for the 3.0 mi2 subwatershed: Forest 77% Residential 11% Open Land 4% Directory: eea -> docs -> dep -> water -> resources -> 71wqar09 dep -> Charles D. Baker Governor dep -> Charles D. Baker Governor dep -> Charles D. Baker Governor dep -> Index of Photographs dep -> Department of environmental protection one winter street, boston, ma 02108 617-292-5500 water -> Water Resource Management Planning 71wqar09 -> 2004 water quality assessment report Download 3.32 Mb. Share with your friends:
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