The Role of Physical Geography on Puerto Rico Water Budget and Potential Groundwater Recharge

The insular Caribbean has limited water resources due to the islands sizes and geomorphic characteristics. This study focused on Puerto Rico to evaluate the role of physical geography on water budget and net infiltration by comparing a baseline climatology (19812010) and multiple drought years (1991, 1994, 1997, and 2015). We used the new Soil-Water-Balance model Version 2.0 from the U.S. Geological Survey to estimate Puerto Ricos water budget. The findings suggested that mountainous and vegetated areas of the island contributed to the greater net infiltration occurring in the central west, north, and eastern Puerto Rico during the baseline. However, the low-lying, less vegetated, and drier southern Puerto Rico located in the rain shadow area of Cordillera Central had less net infiltration over time. During drought events, the decrease in net infiltration and rainfall was most dramatic over central and east Puerto Rico, which together with the reduction in net infiltration that occurred in northern and southern areas resulted in greater concern on water availability. The north and south are home to the North and the South Coast Aquifers, the most important aquifers for drinking water, irrigation, and public supply in Puerto Rico. Those aquifers are both recharged by direct rainfall and by streamflow coming from central Puerto Rico, which make the decreased in rainfall and net infiltration in those areas represent a challenge for the island to have water available to meet its demand during drought events.