IMPROVED FLOOD RISK COMMUNICATION USING NATIONAL FLOOD HAZARD LAYER AND COMMUNITY RESILIENCE ESTIMATES DATA IN MILWAUKEE COUNTY, WISCONSIN

Abstract

Flood Insurance Rate Maps (FIRMs) are primarily used for determining flood insurance rates and if flood insurance is required under the National Flood Insurance Program. FIRMs have several sources of bias and inaccuracy, limiting their capacity to communicate flood risk. This study investigated how FIRMs, which are created with National Flood Hazard Layer (NFHL) data, can be visualized with Community Resilience Estimates (CRE) data from the U.S. Census Bureau to better communicate about flood risk than with NFHL data alone. To conduct this study, one set of flood risk maps showing only NFHL data and another set showing both NFHL and CRE data were created and added to a survey. The survey was administered to Milwaukee County residents to evaluate how successful the flood risk maps were at communicating flood risk. Survey respondents (n=41) indicated that they learned important flood risk information from both sets of maps, but twice as many said that the maps with CRE data were more insightful than the ones without CRE data. The study demonstrated the usefulness of CRE data as a tool to improve flood risk communication.