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Cost-Benefit Analysis of Stormwater BMPs Developed

Dec 16, 2021

Effectively managing stormwater has been an ongoing challenge in coastal South Carolina, as development dramatically increases rates of stormwater runoff and the resulting impacts on natural resources and communities. While a wealth of information exists on how to implement a variety of green stormwater infrastructure (GSI)—such as rain gardens, vegetative swales, permeable pavements, green roofs, and stormwater ponds—less information is available on installation costs and socioeconomic benefits.

A stormwater pond on Kiawah Island.
Consortium researchers at Clemson University and the University of South Carolina Belle W. Baruch Institute for Marine and Coastal Sciences built upon the information published in Low Impact Development in Coastal South Carolina: A Planning and Design Guide by outlining detailed operation and maintenance costs, cost effectiveness, and benefit valuation of a variety of GSI and stormwater best management practices (BMPs). The researchers designed a participatory story map in which stormwater managers entered the type and cost of their installed BMPs in South Carolina’s eight coastal counties. Coastal residents also were surveyed about whether they would adopt GSI for use on their properties and their perceived value of such stormwater BMPs. Several economic analyses were performed to determine costs of installing and maintaining BMPs, and residents’ willingness-to-pay for different types of stormwater infrastructure.
As a result of this research, the S.C. Association of Stormwater Managers, Town of Mount Pleasant, City of Charleston, and Town of Bluffton will be using this methodology for cost-benefit analyses of implementing stormwater BMPs in their communities. In addition, cost-benefit information was incorporated into “Calling the Coast Home,” the Consortium’s continuing education course for realtors.