Consulting Solutions that Work for People and the Environment

Alternatives Analysis of Zemko Dam, East Branch Eightmile River, Salem, CT

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Gomez and Sullivan was retained by The Nature Conservancy to conduct an alternatives analysis including a) dam rehabilitation and installation of a fish passage structure or b) removal of the Zemko Dam in Salem, CT. The project included a hydraulically inadequate earthen dam and spillway located on a coastal stream. The goal was to restore habitat connectivity (anadromous fish), sediment transport and overall ecosystem function. For Phase I, we developed detailed bathymetry and sediment deposit mapping, HEC-RAS hydraulic modeling, conceptual designs for dam rehabilitation and fish passage construction, and an alternatives analysis for dam removal including sediment management. Phase II entailed sediment transport analysis and using the findings to assist in design. In the end, the preferred option was dam removal and we completed design plans and permits. The dam was removed in October 2007.