Arlington County’s Flood Risk Assessment and Management Plan—Integrating Climate Resilience into Infrastructure Planning

Arlington County, Virginia, is developing a Stormwater Program Risk Assessment and Management Plan (RAMP). This paper summarizes how flood modeling and risk assessment were conducted considering climate change for urban interior flooding, riverine flooding, and coastal flooding. The modeling results were used to determine which areas of the county, critical facilities, vulnerable groups, and environmental resources are most vulnerable, based on current and projected flooding with climate change. Detailed risk assessments were then conducted for the watersheds with the highest number of vulnerable receptors. FEMA Hazus tool was applied to assess current and project future damages at neighborhood and watershed scale. In addition, more site-specific risk assessments were conducted for selected public facilities. Flood mitigation alternatives and prioritized strategic investments were developed for mitigating risk, based on economic, environmental, and social equity criteria and quantified project benefits and co-benefits with a measurable benefit-cost analysis methodology. Strategies included storage, conveyance, overland relief, as well as policy and programmatic alternatives.