In August 2011, the waters of the Pawtuxet River rushed over the natural bedrock falls at the river’s mouth, entering salty Narragansett Bay unimpeded for the first time in 300 years.

The restoration of the free-flowing river was the result of the largest ecological dam removal project yet undertaken in Rhode Island.  The project was led by the Pawtuxet River Authority and Narragansett Bay Estuary Program, with funding and technical assistance from more than a dozen federal, state and private organizations (see list below).  The PRA is a state-chartered non-profit organization with the mission of restoring and preserving the Pawtuxet River, while NBEP is one of 28 National Estuary Programs established by Congress under the federal Clean Water Act, with the mission of conserving and restoring the Narragansett Bay ecosystem.

The purpose of the project is to improve the ecosystems of the Pawtuxet River watershed and Narragansett Bay by restoring populations of native migratory fish, such as river herring and American shad, which have been blocked from fully accessing their natural spawning habitat for hundreds of years.  Herring and shad are important components of marine and freshwater ecosystems, providing abundant food for bluefish, striped bass, largemouth bass, herons, ospreys and many other predators—even harbor seals, which winter in the Bay.  In addition, the dam removal will provide modest flood reduction for homes and businesses, and improve water quality in the lower Pawtuxet River. 

Throughout the month of August, contractors used excavators fitted with hydraulic hammers to break up the 150 foot concrete spillway of Pawtuxet Falls Dam, removing it from the river as rubble.  The concrete dam was built in 1924, replacing an earlier timber dam.  The project restored seven miles of free-flowing river habitat to one of the state’s largest and most historic rivers, and reduced the depth of the river by two to three feet along its lower reach.  Where new riverbanks were exposed by the restoration, PRA’s contractors will install native wetland plants and trees to speed the process of natural recovery.  We expect the planting to be complete this fall.

PRA’s construction contractor, SumCo Eco-Contracting of Salem, Mass., developed an innovative water control method for the dam removal which sped the work while reducing project impacts.  Rather than installing large temporary dams or pipelines to divert the river, SumCo removed the dam section by section, using large engineered steel plates and one-ton sandbags to dewater the immediate work area.

We expect to see river herring and shad running back up the Pawtuxet River beginning next spring 2012.  Fish will naturally find their way upstream once the dam is removed; however, R.I. Dept. of Environmental Management will transplant fish from other streams to accelerate the recovery process.  River herring and American shad were once highly abundant in Rhode Island’s rivers, an important component of the marine food web and the basis of a large fishery.  Beginning in the 1700’s, however, more than 600 dams were built in Rhode Island to provide water power for the mills of the Industrial Revolution.  The dams blocked the fishes’ access to historic spawning habitat and led to precipitous declines in their numbers.  Biologists estimate that more than 100,000 herring and shad will return annually to spawn in the Pawtuxet following removal of the dam.

The construction and planting phases cost approximately $600,000, funded primarily by the USDA Natural Resources conservation Service under its Wildlife Habitat Incentives Program and R.I. Dept. of Environmental Management under the Narragansett Bay and Watershed Restoration Bond Fund.  Engineering funds were provided by a number of federal, state and private programs, including the R.I. Coastal Resources Management Council under its Coastal and Estuarine Habitat Restoration Trust Fund.

In developing the restoration project, the PRA and its partners completed major engineering, environmental and cultural studies of the Pawtuxet River, examining river flow, sediments, wetlands, and historic resources in order to ensure that the dam removal will improve the environment of the Pawtuxet River and Narragansett Bay while avoiding adverse impacts to human health or economic uses.  In order to begin construction, extensive permitting was necessary, including approvals by the R.I. Dept. of Environmental Management, R.I. Coastal Resources Management Council, and U.S. Army Corps of Engineers.

In addition to the Pawtuxet River Authority and Watershed Council, support and funding for the restoration partnership are provided by the Narragansett Bay Estuary Program, Natural Resources Conservation Service (NRCS), R.I. Department of Environmental Management (RIDEM), R.I. Coastal Resources Management Council (RICRMC), The Rhode Island Foundation, U.S. Environmental Protection Agency (EPA), National Oceanic and Atmospheric Administration (NOAA), U.S. Fish and Wildlife Service (USF&WS), American Rivers, Save The Bay, R.I. Saltwater Anglers Association (RISAA), Friends of the Pawtuxet, Pawtuxet Village Association, City of Cranston, City of Warwick, Restore America's Estuaries, R.I. Rivers Council, R.I. Corporate Wetlands Partnership, Rhodes-on-the-Pawtuxet, and Hunters Garage.

Engineering: EA Engineering, Science & Technology, Inc., Warwick, RI
Construction: SumCo Eco-Contracting, Salem, MA