Nassau County Back Bays Coastal Storm Risk Management Feasibility 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 New York Description: As a result of Hurricane Sandy in October 2012, Congress passed Public Law 113–2, which authorized supplemental appropriations to Federal agencies for expenses related to the consequences of Hurricane Sandy. The Corps is investigating measures to reduce future flood risk in ways that support the long-term resilience and sustainability of the coastal ecosystem and surrounding communities, and reduce the economic costs and risks associated with flood and storm events. In support of this goal, the Corps completed the North Atlantic Coast Comprehensive Study (NAACS), which identified nine high risk areas on the Atlantic Coast for further analysis based on preliminary findings. The Nassau County Back Bays (NCBB) area was identified as one of the nine areas of high risk, or Focus Areas, that warrants an in-depth investigation into potential coastal storm risk management (CSRM) measures. During Hurricane Sandy, the study area communities were severely affected with large areas subjected to erosion, storm surge, and wave damage along the Atlantic Ocean shoreline, and flooding of communities within and surrounding bays. Along the Atlantic Ocean, surge and waves inundated low lying areas, and contributed to the flooding along the shoreline of the interior of the bays. Hurricane Sandy illustrated the need to re-evaluate the entire back-bay area as a system, when considering risk management measures. The study area includes all of the tidally influenced bays and estuaries within Nassau County, New York, located on Long Island, NY, that are hydraulically connected to the south shore of Nassau County, directly east of Queens County and west of Suffolk County for approximately 98 square miles. The purpose of the study is to determine the feasibility of a project to reduce the risk of coastal storm damage in the back bays of Nassau County, New York, while contributing to the resilience of communities, critical infrastructure, and the natural environment.   The study is needed because the study area experiences frequent flooding from high tides, spring tides, sunny day flooding, and coastal storms; is considered at high risk to coastal storm flooding with an associated threat to life safety; includes a degraded back bay ecosystem; and is susceptible to relative sea level change.  The overall objective of the NCBB CSRM Feasibility Study is to develop solutions to reduce damages from coastal flooding affecting critical infrastructure and highly vlunerable risk areas.  The specific planning objectives to apply to the entire study area over the 50-year period of analysis (2030 to 2080) are: Reduce potential life loss related to coastal flooding in the study area through 2080, Reduce the risk of coastal storm damage to public infrastructure and important societal resources, as well as highly vulnerable portions of southern Nassau County through 2080, and Contribute to the long-term sustainability and resilience of coastal communities in southern Nassau County through 2080. The study will evaluate a broad array of management measures including structural (floodwalls and levees), non-structural (building retrofits, land use management, managed retreat, and early flood warning systems), and natural and nature-based features (NNBF) (beach, wetland, and SAV restoration; living shorelines, reefs, and green stormwater management).  Opportunities for innovative designs, technologies, materials, and combinations of standard measures are expected to be key to managing coastal risks and promoting resilience.

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