Fully Coupled Atmospheric‐Hydrological Modeling at Watershed Scale: A Case Study with WRF-Hydro for Western Puerto Rico

Weather-related disasters have seen an increase in their frequency since 1980. For Puerto Rico, a territory of the United States in the Caribbean, the past decades have been plagued with constant floods, whose impact range from limited to catastrophic. This can be attributed to the topographic features and weather patterns of a tropical climate, where constant high temperatures lead to high intensity convective rainfall. Even though any rainfall event can lead to a flood, they are more likely to occur during the hurricane/rain season. Currently, the method used by the National Weather Service for flash flood analysis in Puerto Rico is the Flash Flood Guidance. For the island, the Flash Flood Guidance divides the territory in multiple regions and provides a single value for each one of them. For Puerto Rico, whose topography and weather patterns experience drastic changes in short distances, this guidance value may not be an accurate representation for all the area contained within each of the subdivisions. This study implemented the Weather and Research Forecasting Hydrological modeling system (WRF-Hydro) for multiple watersheds in Puerto Rico.

The work herein present early results for the Añasco river basin at western Puerto Rico. WRF-Hydro improved the spatial resolution over the current system, however extensive validation and calibration is still needed. Recommendations and path forward are also discussed.