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Green Lake Dam
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Green Lake Dam (State ID: 011-0388, small Hazard Class C) is located within the Town of Orchard Park, in Erie County, NY. The dam impounds Green Lake, which is located west of New York Route 240. Green Lake Dam was constructed in 1909. It is approximately 25 feet high and about 350 feet long across the crest. The surface area of the lake is approximately 20 acres with a contributing watershed of approximately 2.9 square miles.
The service spillway is located at the east (right) abutment of the dam. The spillway is concrete with a width of about 36 feet and weir length of approximately 32 feet. McMahon & Mann worked with KHEOPS Architecture, Engineering & Survey, DPC to complete a dam safety inspection and Engineering Assessment Report (EAR). Deficiencies identified in the EAR included insufficient spillway capacity and upstream and downstream slopes that were too steep.
McMahon & Mann, KHEOPS and Golder Associates developed remedial plans that included revising the upstream and downstream slopes and replacing the spillway with a labyrinth spillway. Construction was completed in 2016 with McMahon & Mann monitoring the geotechnical aspects of construction.