Dam Removal – A Tool for River Restoration on the Naugatuck River

The Naugatuck River and its tributaries once supported abundant anadromous fish runs. These runs ceased during the industrial revolution due to the construction of numerous run-of-the-river dams and poor water quality. Recent and anticipated water quality improvements now justify a parallel effort to restore anadromous fish runs to the Naugatuck River basin. This watershed-wide restoration project focuses on fish passage at eight obsolete industrial dams on the Naugatuck and Mad Rivers, ranging in height from 1.2 to 6 meters. Multiple fish passage alternatives were considered prior to recommending that four of the eight dams be fully or partially removed, an instream by-pass channel, rock ramp fishway and a fish ladder will be constructed around three others. The final dam is still under study and it is anticipated that dam removal will be recommended. To date, four dams have been removed. This paper will focus on the fish passage alternative analysis prepared for this project and the issues that arose during design and construction of the first four dam removals.