Charleston Peninsula Coastal Flood Risk Management Study

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Other Agencies with Actions or Authorizations: Department of the Interior, Fish and Wildlife Service Department of Commerce, National Oceanic and Atmospheric Administration Advisory Council on Historic Preservation Description: The Charleston Peninsula Coastal Flood Risk Management Study is a federal feasibility study that investigates coastal storm impacts on the Charleston peninsula. In partnership with the City of Charleston and its stakeholders, the study also explores economically-viable and environmentally-sound solutions to mitigate coastal storm risks. The feasibility study began in 2018 and is 100 percent federally funded through Emergency Supplemental Funding. This feasibility study is one piece of the City’s overall comprehensive flooding strategy. In the last several years, the City has initiated several flood reduction strategies, including its Flooding and Sea Level Rise Strategy, a vulnerability assessment, rehabilitation of Low Battery Wall, Dutch Dialogues and major drainage projects. This study primarily addresses the risks of coastal storm surges. In conjunction with other flood mitigation efforts, the study also takes tidal flooding and sea level rise into account in its analysis. In April 2020, the U.S. Army Corps of Engineers published a draft Feasibility Report / Environmental Assessment outlining study findings and general storm risk reduction measures, including a perimeter storm surge wall with pump stations and nonstructural measures. In the months following, the study used public and agency feedback, as well as results from ongoing modeling and analysis, to continue optimizing the proposed plan. Among some of the plan refinements include removal of the wave attenuator, reducing the project’s initial cost; increasing the sea level rise curve to evaluate more severe SLR scenarios; ongoing modifications to the storm surge wall alignment to reduce costs without impacting benefits; and additional detailed interior hydrological modeling. In March 2021, the study transitioned from an Environmental Assessment (EA) to an Environmental Impact Statement (EIS). Conducting an EIS allows USACE to do a more robust analysis on project impacts and more clearly define measures to mitigate for those impacts. It also allows for expanded public engagement on the proposed plan through public meetings and release of a revised and updated draft report for public review.

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