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native macrophytes and the low Secchi disk transparency documented by ENSR in 2002 (ENSR, 2003).

Aaron River: The Aquatic Life Use is assessed as impaired for this segment of the Aaron River based on the presence of the barrier to anadromous fish migration for the entire length of this segment as well as the presence of a dense infestation of a non-native macrophyte species which compromise 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). Flow alterations from the water supply diversion may affect some of these water quality conditions and are also of concern.

3.2 Loss of Fish Runs and Potential Spawning Habitat

The Gulf Watershed

A poorly designed deteriorating notched weir-pool ladder at Hunters Pond is impassible and if replaced the river herring population has the potential to increase substantially. While DMF does not generally endorse the development of anadromous fish populations in public water supplies, the Town of Cohasset has expressed interest in maintaining such a herring resource in the reservoirs. In addition to river herring, rainbow smelt are known to spawn in the stream below Hunters Pond (Rebak, 2004). Smelt spawning habitat was documented in The Gulf for approximately 166 meters downstream from the face of the dam as well as in the mill channel. Several stretches of clean gravel and cobble were found along this reach however there were also areas of sediment deposition (eroded beach sand), noted as a concern by DMF biologists (Chase in preparation). Since water depth fluctuations may be contributing to elevated smelt egg mortality, a volunteer stream flow gauge station should be established near the smelt spawning habitat in the Gulf to evaluate stream flow conditions in relation to the habitat requirements of smelt and other diadromous species. Large numbers of glass eels were seen during April in both seasons. The observations of glass eels relative to other river systems in this study indicate that if passage were permitted, Bound Brook may be a productive river system for eel.

3.3 Loss of Priority Land and Aquatic Habitat

Loss of Wetlands: The restoration of the Greenbush commuter railroad service is proposing to shift the tracks approximately 10 feet to the north of the existing right of way to accommodate an existing sewer line. This will result in approximately 7,400 ft2 of permanent fill in the salt marsh on the banks of Musquashcut Brook (the waterway between the pond and the Gulf) along with temporary alterations to the marsh and waterway. The wetlands variance for Cohasset requires wetland replication and enhancement at two sites bordering the Great Swamp in Cohasset (Special Conditions #30-49) as well as erosion and sedimentation plans (Special Condition #22) and replanting all disturbed areas (DEP, 2006).

Loss of Tidal Marsh in the Gulf: Musquashcut Pond

Musquashcut Pond is 70 acres, shallow, brackish and designated a Great Pond separated from Massachusetts Bay by North Scituate barrier beach. It is surrounded by residential development on two other sides. The pond is listed in Category 5 of the draft 2006 Integrated List of Waters due to impairment from excess algal growth, chlorophyll, dissolved oxygen saturation, total phosphorus and

South Coastal Watershed Action Plan 9/12/2006 Watershed Action Alliance


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