Designing for Climate Change: Flood Risk Mitigation Using Optimization (Alexandria, VA)

The City of Alexandria (the City) has experienced repeated and increasingly frequent flooding. The City initiated a study to update stormwater management modeling and evaluate alternatives to mitigate flooding in the entire Four Mile Run (FMR) East watershed within the City. The effort consisted of a pilot area optimization, the results of which were progressed to preliminary design, as well as the wider Four Mile Run East service area analysis used to update the City of Alexandria’s stormwater masterplan. The findings of the study resulted in the City of Alexandria selecting a flood mitigation strategy that addresses the projected 2070 climate scenario. Described are the results of the climate resilience study, including the alternative analysis optimization, and lessons learned from the pilot that were applied to the wider FMR watershed and are applicable to other planning/optimization projects.