Norfolk is a strategic coastal city, bordered on the north by the Chesapeake Bay, subject to Nor’easters, and home to the largest Navy installation in the world.
To tackle a planning priority faced by many coastal cities, the City of Norfolk contracted a series of coastal flooding studies to identify risks and develop mitigation options to address the combined impacts of extreme tides, storm surges, and extraordinary precipitation events. The work was groundbreaking for Virginia in considering and publishing the specific impacts of sea level rise on project feasibility and long-term benefits. Moffatt & Nichol, on a team under a multiyear, on-call contract, was responsible for modeling flooding from combined precipitation and storm surge events over nearly two-thirds of Norfolk’s storm watershed area, including the 19-square-mile Lafayette River watershed. Study areas included the historic Hague community and downtown business district. The model results were used to evaluate conceptual alternatives for mitigating flood vulnerability and to prepare conceptual and preliminary design of preferred alternatives for four watersheds. The modeling was also used to support coordination with FEMA to maintain the downtown business district’s designation as a protected area on the city’s current preliminary Flood Insurance Rate Map. Moffatt & Nichol also assisted Norfolk to coordinate potential federal funding opportunities with the Navy and U.S. Army Corps of Engineers.