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Water: Nonpoint Source Success Stories

Rhode Island: Section 319 Success Stories, Vol. III

Begin Page Links Story 1  |  Story 2  |  State Water Quality Site Exit EPA Disclaimer  End Page Links Story Separation Bar Curran Brook Sedimentation Pond:
Multiple Partners Construct Storm Water Control System

Jim Riordan
Rhode Island Department of Environmental Management
235 Promenade Street
Providence, RI 02908
401-222-4700 (ext. 4421)
Primary Sources of Pollution:

urban storm water runoff
Primary NPS Pollutants:


bacterial contaminants

Project Activities:

construction of storm water control system

monitoring in progres

The Pawtucket Water Supply Board (PWSB) reservoir system in Rhode Island serves the cities of Pawtucket and Central Falls and the southern portion of the town of Cumberland. The system serves some 110,000 customers. The PWSB's water resources derive from both surface water and groundwater. The four surface water reservoirs—Diamond Hill Reservoir, Arnold Mills Reservoir, Robin Hollow Pond, and Happy Hollow Pond—are the major impoundments controlled by PWSB. The water treatment plant for PWSB is located at the southern end of Happy Hollow Pond.

At the outset of the project, Rhode Island Department of Environmental Management's (RIDEM's) most recent assessment of Happy Hollow Pond determined that the reservoir was only partially supporting its designated use. The reservoir had high levels of nutrients, bacterial contaminants, siltation, and organic compounds, which were most probably conveyed by runoff from the highly urbanized surroundings.

Robin Hollow Pond, located in the lower portion of the Pawtucket Water Supply watershed, feeds directly into Happy Hollow Pond, which is an EPA-designated community water supply. Robin Hollow Pond receives runoff from the most urbanized portion of the watershed. The urbanized area is to the west of the pond in the town of Cumberland. The project focused on removing nutrients, bacterial contaminants, siltation, and inorganic compounds from runoff in the urbanized watershed, thereby decreasing the need for costly water purification treatments.

State-of-the-art storm water control system

The project consisted of designing, permitting, and building a state-of-the-art storm water control system to replace an undersized and antiquated sediment pond. The new system includes a sediment forebay, water quality pond, and artificially created wetland to treat the storm water during wet weather events. Project partners included the Northern Rhode Island Conservation District, PWSB, the U.S. Department of Agriculture's Soil Conservation Service (now the Natural Resources Conservation Service), RIDEM and EPA Region 1.

Model project

The system was completed in October 1999. It has been featured in several field reviews, including the New England Interstate Water Pollution Control Commission's 2000 Annual Nonpoint Source Conference. PWSB has also been monitoring the system to determine its effectiveness in removing the pollutants of concern. 


Begin Page Links Story 1  |  Story 2  |  State Water Quality Site Exit EPA Disclaimer End Page Links Story Separation Bar
Galilee Salt Marsh Restoration:
Undersized Culverts Replaced with Self-Regulating Gates

Jim Riordan
RIDEM Office of Water Resources
401-222-4700 (ext. 4421)

Brian Tefft
RIDEM Division Fish and Wildlife
P.O. Box 218
West Kingston, RI 02892

Primary Sources of Pollution:

dredge and fill of tidal channel/salt marsh
Primary NPS Pollutants:

Project Activities:

installation of self-regulating sluice and tide gates

68 percent reduction of Phragmites

restoration of 84 acres of salt marsh habitats and 14 acres of tidal creeks and ponds

The coastal features of southern Rhode Island provide a breathtaking variety of special habitats. The Galilee Bird Sanctuary is a 128-acre coastal wetland complex owned and managed by the Rhode Island Department of Environmental Management (RIDEM), Division of Fish and Wildlife. The sanctuary is east of the port of Galilee and is bounded by the Galilee Escape Road to the north and Sand Hill Cove Road to the south.

Unfortunately, much of the Galilee Salt Marsh has led a fractured existence. During the 1950s unconfined dredge spoil from the Port of Galilee was deposited over portions of the western side of the salt marsh where the Galilee Bird Sanctuary is located. This disposal filled in a tidal channel that had been present in this location and significantly altered the natural hydrology of the marsh.

During a 1954 hurricane, the extreme flooding of Sand Hill Cove Road trapped the residents of Great Island. To prevent this from occurring again, the State Division of Public Works constructed the Galilee Escape Road in 1956. Construction of the Escape Road fragmented the previously continuous salt marsh, eliminating in the process about 7 acres of valuable marsh habitat. Restriction of tidal flushing transformed the once-productive salt marsh into dense thickets of Phragmites and shrubs, causing reduction of natural coastal wetland habitats for migratory waterfowl, shorebirds, fish, and shellfish.

Self-regulating gates

The Galilee Salt Marsh Restoration Project was a multimillion-dollar effort with a number of contributing partners, including the Rhode Island Department of Transportation, U.S. Army Corp of Engineers, Ducks Unlimited, U.S. Fish and Wildlife Service, RIDEM Fish and Wildlife, and other agencies, under the auspices of the Coastal America Program.

Section 319 funding contributed to the restoration efforts with a $64,300 grant to replace the undersized culverts and install self-regulating sluice and tide gates. The self-regulating gates allow for minimum intervention and maintenance and were devised as an alternative to more costly and operation-intensive electric gates. The gates operate using a system of floats and balances that are precisely calibrated to close when water reaches a preset level.

Impressive results

Marsh restoration was completed and dedicated October 1997. Results have been strong. Phragmites was reduced by 68 percent at the completion of the 1999 growing season, and height was reduced from 11 feet to 3.5 feet. Fish and wildlife populations have responded to the restoration in dramatic fashion: finfish recolonized the tidal creeks within days following opening of the tide gates. Waterfowl (duck and geese), including the American black duck, use the restored marsh extensively for nesting and feeding and during migration. In total, approximately 84 acres of salt marsh habitats and 14 acres of tidal creeks and ponds were restored.

Complete restoration is expected to take 10 years or more. The project has been an enormous success, and the salt marsh has been designated a bird sanctuary. The project is an excellent demonstration of collaboration among various branches of government.


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