Governor Donald L. Carcieri and W. Michael Sullivan, Director of the Department of Environmental Management (DEM), today celebrated the completion of the high-hazard Stillwater Reservoir Dam reconstruction project in Smithfield.

“By reconstructing the Stillwater Reservoir Dam and bringing it up to current standards, we are not only maintaining and upgrading an important part of our state’s infrastructure, but we are ensuring that this structure can withstand storms,” Governor Carcieri said.

“That, in turn, makes our state better prepared for flooding and heavy rainfalls. This $2.4 million project is about taking the necessary steps to protect our infrastructure, our communities and our residents. It’s about ensuring public safety.”

The 660-foot earthen Stillwater Dam, with a 100-foot concrete spillway, is located in Smithfield, and is the third high hazard state-owned dam repaired by DEM in the past six years. “Because it had been in poor condition, DEM purposely kept the water level below the spillway crest to prevent further erosion of the structure,” said DEM Director Sullivan. “However, it remained a popular spot for public recreation such as fishing, boating, and sightseeing. This site, which includes new fishing stations and parking, will continue to be used for recreation, and is now also easily accessible to those with disabilities.”

The spillway, located on the western edge of the earthen embankment, has been completely rebuilt to the previous width and crest elevation measurements, and has the capacity to withstand a 100-year flood event. A bypass channel has been incorporated into the spillway so that water can continue to be provided via regulated flow to the Smithfield wastewater treatment plant downstream during drought conditions. With minor modifications, the bypass channel can serve as a fish ladder in the future.

Both the north and south dikes of the dam have been completely rebuilt to provide easy maintenance of the low back slopes as well as erosion protection from storm events. To bring the dam up to current standards, an emergency spillway has been constructed on the south dike to handle overflow flooding in the case of an approximately 500-year storm event. A new, paved, 16-vehicle parking lot, with drainage improvements, and a refurbished gate house structure complete the work.

The Stillwater Reservoir Dam was constructed in 1910 for the Woonasquatucket Reservoir Company, an association of businesses that included Worcester Textile, Narragansett Foundry, and others. The dam was used to provide a consistent supply of water to ponds downstream for several mills and foundries.

The 32-square-mile drainage area contributing to the reservoir consists of rolling woodlands, swamps, and open and developed land. There are seven dams immediately downstream from the reservoir including Stillwater Pond Dam, an unnamed dam, Capron Pond Dam, Georgiaville Pond Dam, Greystone Mill Pond Dam, Allendale Mill Pond Dam, and Lyman Mill Pond Dam. Failure of the Stillwater Reservoir Dam could cause sequential failure of one or more of these dams, and inundation of surrounding areas.

The Stillwater Reservoir Dam is operated and maintained by DEM's Division of Fish and Wildlife, and was reconstructed under the oversight of DEM's Division of Planning and Development. An evaluation of the dam was conducted in 2000 by the Louis Berger Group of Providence to develop corrective measures. Design work, including a geotechnical investigation, a site topographic survey, and a detailed hydrologic and hydraulic analysis, was done by GZA GeoEnvironmental of Providence. The contractor for the reconstruction, which began in June 2004, was J.H. Lynch & Sons of Lincoln, and full time project management was provided by Cataldo Associates of Johnston. Funding for the $2.4 million reconstruction project was from the RI Capital Fund, with an additional $20,000 contribution from the Governor's Commission on Disabilities.

Previous high-hazard state-owned dams repaired under DEM's oversight are the Olney Pond Dam in Lincoln, at a cost of $400,000, and the Bowdish Dam in Glocester, at a cost of $1 million.

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