The potential changes in stormwater runoff and flooding were computed for the Florida Southeast Coasts Basin (7117 km2), which spans from Florida City through Fort Pierce. A large-scale process-based hydrologic model was developed, calibrated, and validated for the basin with Storm Water Management Model 5.1. We incorporated the historical (2010s = 2004-2013) observations and projected changes in climatic and land cover variables during the future timeframes (2050s = 2044-2053; 2080s = 2076-2085). Our results suggested that annual stormwater runoff volume would increase by 80-118% by 2050s through 2080s in the Florida Southeast Coasts Basin. The urban centers such as the greater Miami, Fort Lauderdale, and West Palm Beach would experience the highest increases in runoff. This implies that flooding risk southeast Florida would be doubled in in the next 30-60 years. These findings can guide stormwater management in coastal built environments in southeast Florida and beyond.
