Habitat Restoration & Protection Database

The West River Dam was built in 1920 to keep the New Haven Harbor tidal water out of the Olmsted-designed Reflecting Pool and Edgewood Park, which are both upstream. The dam was designed with 12 standard flapper-style wooden tide gates to maintain stormwater drainage out to New Haven Harbor and Long Island Sound. But the installation of this structure prevented both tidal water and fish from passing upstream. The negative impacts of the dam include a greatly dampened tidal amplitude. Although still tidal because the wooden tide gates leak, the high tide line upstream of the dam is much lower than it is on the downstream side. This results in degradation of tidal wetlands and the rest of the estuarine embayment upstream, in addition to the unpassable obstruction to diadromous fish. The dampened tide also means much less salt water was getting upstream. In conjunction with the draining of the marsh from the tide gates, the lower salinity created prime habitat for the invasive common reed, Phragmites australis. The center of the West River is the boundary between the Cities of New Haven and West Haven.