EFFECTS OF GLOBAL WARMING ON HURRICANE-INDUCED FLOODING

Global simulation models used to predict climate change typically have resolutions too coarse for resolving small drainage basins, creating a major obstacle to evaluating the hydrologic impacts of climate variability. The writers circumvent this difficulty by using a physical model for severe hurricanes to derive changes in hurricane rainfall under a predicted global warming. The modified rainfall is then transferred to a linked hydrologic-hydrodynamic model to compute the impact of global warming on hurricane-induced flooding in a susceptible watershed. As an example, using simulations of tropical, doubled-CO2 climate change, the hurricane model predicts a 40% precipitation increase for severe hurricanes affecting southeastern Florida. The 40% increase is assumed for a 100-year, three-day event used for flood-management planning in South Florida and applied to the Basin Runoff and Streamflow Simulation (BRASS) model of the Western C-11 drainage system. The increased precipitation provokes substantially greater flooding that could negate most of the benefits of present water-management practices in this basin.