Identifying cost-effective opportunities to improve flooding conditions in urban settings is challenging. One residential neighborhood located along Congers Creek within Rockingham County has struggled with frequent flooding events involving structural and roadway flooding. Congers Creek is largely an open channel conveyance system with culvert crossings, but no FEMA floodplain has been mapped for the stream. A watershed analysis has been completed of the existing conveyance system using PCSWMM to determine existing hydrologic/hydraulic performance of the conveyance system and identify flood vulnerable structures.
With existing conditions modelling that indicates 28 residential structures along Congers Creek are located within the 10-yr floodplain, Rockingham County is eager to implement improvements to improve flooding conditions in this watershed. Three strategies to reduce flooding along Congers Creek have been recommended and include 1) infrastructure improvements to increase conveyance capacity 2) increased storage capacity by evaluating proposed/retrofit detention ponds 3) implementation of programmatic and administrative tools to manage future development in the watershed. Rockingham County is moving forward with implementation of a large detention basin that, as modeling indicates, will significantly improve flooding conditions in the watershed.