Mapping the future: Leveraging GIS to analyze rainfall, groundwater, and temperature variability in the Tampakan-Lutayan Watershed

Abstract

The Tampakan-Lutayan Watershed is a vital hydrological system in the southern part of the Philippines that supports agricultural, settlement, and environmental activities. However, there is limited integrated spatial assessment of the watershed to identify the physical and environmental characteristics in the upstream, midstream, and downstream areas of the watershed. This study aimed to characterize the Tampakan-Lutayan Watershed using Geographic Information System (GIS), remote sensing technology, and Digital Elevation Model (DEM) analysis. Specifically, this research investigated the elevation, slope, rainfall, temperature, groundwater potential, soil erosion, and land use/land cover characteristics in the Tampakan-Lutayan Watershed. Watershed delineation using a Digital Elevation Model (DEM) and ArcSWAT was conducted to characterize the Tampakan-Lutayan Watershed. Moreover, the study estimated soil erosion using the Revised Universal Soil Loss Equation (RUSLE). The results revealed significant spatial variability in the Tampakan-Lutayan Watershed. The upstream area in Tampakan exhibited higher elevation, steeper slope, higher rainfall, lower temperature, and greater soil erosion potential. In contrast, the midstream and downstream areas in Koronadal and Lutayan had lower elevations, gentler slopes, warmer temperatures, and relatively lower erosion risk. LULC analysis from 2017 to 2023 also indicated notable landscape changes associated with vegetation shifts, agricultural transition, and changes in built-up and inland water areas. These findings highlight the importance of integrated watershed management, particularly in promoting sustainable land-use planning, reforestation, erosion control, and community-based conservation for long-term watershed sustainability.