A GIS-Based Decision Support Tool for Building Flood Resilience in the Community Rating System

Building flood resilience has become a priority in the United States as flood risks continue to rise. The National Flood Insurance Program’s Community Rating System (CRS) serves as an excellent framework for local-level resilience planning by incentivizing a wide range of flood management practices with CRS credits, which are exchanged for community-wide flood insurance discounts. Despite the short-term and long-term benefits, resource barriers and limited technical capacity constrain communities’ ability to participate in the program. In this thesis, a GIS-based decision support tool is developed to facilitate communities’ participation in the CRS. Specifically, the tool improves reproducibility and streamlines the process of modelling Open Space Preservation (OSP) areas in the floodplain. OSP is a highly incentivized CRS activity that is also promising in terms of flood protection. Most communities already preserve lands in the floodplain, indicating a missed opportunity for policy-holders across the United States to receive financial benefit. Furthermore, OSP aligns with a growing national interest in the use of natural infrastructure for flood protection. Implementing OSP, however, requires extensive GIS analysis, and many communities lack the technical capacity needed to fulfill the program requirements. To address this challenge, the GIS tool identifies areas that are already preserved and calculates credit estimates, providing communities with an indication of the financial benefit they are eligible to receive. In addition, the tool implements a novel methodology for mapping unprotected open space areas in the floodplain that could be eligible for CRS credit if preserved. These maps, along with estimates of future crediting scenarios, help communities pursue additional OSP credits through flood resilient land-use planning. The tool is applied to communities in the Commonwealth of Virginia as a case study. Statewide, over 34,000 unclaimed OSP credits are identified, suggesting an opportunity for significant expansion of the CRS in Virginia. Across the country, communities can use the GIS tool to perform necessary GIS work more quickly and easily, engage with stakeholders, and make a strong financial argument for proactive flood management practices.