CONCORD, Mass. – The U.S. Army Corps of Engineers, New England District completed the Pawcatuck River Coastal Storm Risk Management (CSRM) feasibility study and proposes a plan to reduce potential storm and flooding impacts to Westerly, Charlestown, South Kingstown and Narragansett, Rhode Island.
The study area included about 28 miles of moderately developed coast in the towns of Westerly, Charlestown, South Kingstown and Narragansett in Washington County. The floodplain completely encompasses the coastal barrier beaches and salt ponds in the area. There is a demonstrated need for coastal resiliency measures to be implemented in south coastal Rhode Island. Residential and commercial properties in the Pawcatuck River coastal floodplain are all vulnerable to inundation from coastal storms.
This study was conducted under the Disaster Relief Appropriations Act of 2013 for Hurricane Sandy impacts, according to Project Manager Christopher Hatfield, of the Corps of Engineers, New England District, Planning Division in Concord, Mass.
The Recommended Plan for the Pawcatuck River CSRM project consists of elevating the first floors of 247 structures in the four study area communities. The first floors will be elevated to a height corresponding to the Federal Emergency Management Agency (FEMA) designated Base Flood Elevation (BFE), ranging from +11 feet North Atlantic Vertical Datum of 1988 (NAVD88) to +17 feet NAVD88, plus 1 additional foot in accordance with Corps/NFIP standards, 0.8 feet to account for intermediate sea level rise over the next 50 years, and another 0.2 feet to account for sea level rise which has occurred since the current sea level was published (1992) to present. Properties eligible for elevation are: 49 structures in Westerly; 45 structures in Charlestown; 72 structures in South Kingstown; and 81 structures in Narragansett.
Twenty-one primarily commercial structures (6 in Westerly, 4 in South Kingstown, and 11 in Narragansett) are also included in the recommended plan for flood proofing (e.g. utility relocations, sealants, closures, etc.). They consist of large multi-story hotels, sheet metal buildings, brick on concrete slab buildings, etc.
The Pawcatuck River CSRM feasibility study considered a range of structural and nonstructural measures to reduce the risk of storm damage. Through an iterative planning process, potential coastal storm risk management measures were identified, evaluated and compared. Initial screening of alternatives determined that detailed study of structural (sheet pile floodwalls and tide gates), soft structural (beach fill/nourishment), and nonstructural (elevation and buyout of properties) alternatives should be conducted in Westerly due to the density of development there. Conversely, only non-structural alternatives made sense for full evaluation in the towns of Charlestown, South Kingstown and Narragansett.
The non-Federal project partner for the study and project moving forward is the Rhode Island Coastal Resources Management Council.
The proposed plan was coordinated with: U.S. Fish and Wildlife Service; U.S. Environmental Protection Agency; U.S. National Marine Fisheries Service; Rhode Island Department of Environmental Management, Office of Water Resources, Bureau of Natural Resources, Division of Fish and Wildlife - Marine Fisheries; Rhode Island Coastal Resources Management Council; The Nature Conservancy, Rhode Island Chapter; Save the Bay; Wood-Pawcatuck Watershed Association; Rhode Island Historical Preservation and Heritage Commission; Narragansett Indian Tribe – Tribal Historic Preservation Office; and the towns of Westerly, Charlestown, South Kingstown and Narragansett.
A copy of the final Chief’s report and final integrated feasibility report will be available via the website https://www.nae.usace.army.mil/Missions/Projects-Topics/Pawcatuck-River-CSRM-Feasibility-Study/.