Groundwater Recharge Potential Mapping Using Hydrological Modeling and Remote Sensing in the Lake Lanao Catchment, Philippines

Abstract

Groundwater is an increasingly important component of water resources in large watershed systems, particularly in regions where surface water is subject to seasonal variability and increasing demand. In the Philippines, major catchments such as the Lake Lanao watershed play a critical role in supporting domestic use, agriculture, and regional water security, yet spatial information on groundwater recharge potential remains limited. This study mapped groundwater recharge potential zones within the Lake Lanao catchment using an integrated approach combining hydrological modeling and remote sensing techniques. The Soil and Water Assessment Tool (SWAT) was applied using data on meteorological conditions, slope gradient, soil type, LULC (land use and land cover), drainage density, and lineament density to simulate hydrological processes relevant to recharge estimation. The resulting groundwater recharge potential map was classified into five zones: Poor, Low, Moderate, Good, and Excellent. Results show that 19.34% (158km2) of the catchment area falls under the “Excellent” recharge category, 17.26% (141km2) under “Good,” 40.15% (328km2) under “Moderate,” 14.57% (119km2) under “Low,” and 8.69% (71km2) under “Poor.” Overall, the catchment is dominated by moderate recharge potential zones. Estimated groundwater recharge rates range from 301 mm to 360 mm annually across the catchment. The findings provide spatially explicit information that can support groundwater resource planning, watershed management, and sustainable water allocation strategies in the Lake Lanao catchment.