IMPROVING THE KARST GROUNDWATER CATCHMENT AREA ISOHYET MAP OF RIO TANAMA, ARECIBO PUERTO RICO, USING A GEOGRAPHIC INFORMATION SYSTEM

This investigation focuses on the improvement of the previous Charco Hondo (CH) isohyetal map method to outline catchment boundaries and size. Currently, no catchment area is determined for CH by the United States Geological Survey (USGS) and the goal of this study was to obtain a faster and more cost-effective method to describe the physical boundaries of a karst groundwater drainage area. By correlating discharge data from the USGS, with radar-rainfall data from the National Oceanic and Atmospheric Administration, Advanced Hydrologic Prediction Service (NOAA, AHPS), the resultant map should show the physical boundaries of the catchment area in CH, at Río Tanamá. High rainfall resolution data obtained from NOAA, AHPS; and different interpolation tools in the Geographic Information System (GIS) program ArcMap 10.1 were used to improve a isohyetal map of Río Tanamá at CH region. As part of this investigation, a yearly record measure of the Total Karst Flow (TKF), and a calculation for the drainage areas of CH and Near Utuado (NU) catchments was estimated in Excel. Although the resultant map in this investigation does not show a firm relation with the boundaries of the catchment area in the study area, the results did demonstrate a significant relation between discharge high peaks and rain events.