SumCo Eco-Contracting has completed dozens of dam removals, dam rehabilitations, fish passage, and associated river restoration projects.
Our dam rehabilitation construction projects include vegetation removal and embankment repairs; sheet pile cutoff walls and cofferdams for excavation support; slide gates; underdrain systems; new spillway construction; complete concrete repairs, re-facing, and raising of spillway approaches and channel walls; shutter wall stanchion replacements; associated culvert replacements; access road rehabilitation; regrading, restoration and more.
Removal of aging dams no longer serving their original purpose (power generation, water supply) restores fish passage; reconnects instream and riparian habitat; improves water quality; and enhances riverine functions such as sediment and organic matter transport. Dam removal also eliminates owner maintenance costs and liability, including risk of injury and potential for catastrophic dam failure.
Depending on dam size, project purpose and complexity, our dam removal work may include a variety of elements, including excavation; stockpile management and segregation; dewatering, temporary channel diversion and filling of overflow channels; demolition of the dam and related or adjacent structures; on-site reuse of stone materials; and reuse or off-site disposal of impounded sediment. Often accompanying dam removals or breaches is restoration of the local ecology, including bank and channel stabilization; grade control riffle at a dam’s former location; and riparian shrub plantings.
Not all dams can be removed. We have constructed fish passage solutions that leave dams intact. Project examples include a rock ramp fishway at Kenyon Mill Dam (Kenyon, Rhode Island) to pass migratory fish over the dam, and the largest natural bypass channel east of the Mississippi for fish passage around the Howland Dam (Howland, Maine). In addition, we have also completed a number of dam modifications, such as the repair and and new spillway construction at Haskell Pond Dam (Gloucester, Massachusetts).