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Session B6- Installation of Denil fishways and eel ladders at brownfield sites

EA Engineering, Science, and Technology, Inc., the U.S. Department of Agriculture Natural Resources Conservation Service, and the Woonasquatucket River Watershed Council have successfully designed, permitted, and constructed Denil fishways and eel ladders at the Rising Sun Mills and Atlantic Mills Dams, the first and third dams on the Woonasquatucket River, a federally designated American Heritage River. The Woonasquatucket River has a number of low head dams from former industrial uses that prevent passage of diadromous fish. The fish ways at these two dams, combined with the two dam removals at Paragon Mills and Dyerville Dams, thesecond and fourth dams, opened over linear miles and 150 acres of habitat to diadromous fish, including American shad, blueback herring, alewife, and American eel. Providing fish passage at these two urban river settings presented numerous engineering and permitting challenges to address historical and archaeological considerations, contaminated sediment management, and state and federal regulatory requirements. Rising Sun Mills Dam and Atlantic Mills Dam are located adjacent to capped Brownfield sites, and the Denil fishways had to be designed to maintain the integrity of the Brownfield caps. Both fish ways required modifications to the existing dam structures after installation of cofferdams to address unknown conditions. The Rising Sun Mills fish way required modification to the deteriorated timber gate for the fishway exit channel and stabilization of the timber spillwayapron for construction of the fishway entrance. The spillwayabutment at Atlantic Mills Dam was found unstable and had to be replaced with a new concrete abutment between the spillway and the fishway exit channel. Both projects included design and installation of eel fish ways subsequent to completion of the Denil fishways. Solar panels were used to operate the attraction water pumps since there were no nearby power sources.