Geospatial Governance for Sustainable Water Resources Management: Integrating SWAT Modeling, Satellite Data, and Hydrogeological Units in Padsan River Watershed

Abstract

Groundwater governance in the Philippines is challenged by limited irrigation infrastructure, reliance on aquifers, and increasing climate variability. This study presents a geospatial governance framework for sustainable water management in the Padsan River Watershed (PRW), located in Northern Luzon. The framework integrates the Soil and Water Assessment Tool (SWAT), bias-corrected satellite climate products, hydrogeological unit mapping, and high-resolution estimates using building-footprint-based population mapping derived from Google building footprints. The integration approach has yielded an efficient hydrological model that effectively captures the occurrence of the water balance. The model simulation results show pronounced seasonality in river discharge, significant variation in groundwater recharge across Land Use/Land Cover (LULC), and spatial mismatches between irrigation service areas and productive aquifers. Population overlays reveal that the majority of residents rely on highly productive but potentially stressed groundwater systems, while several potential irrigation zones remain underserved. These findings underscore the importance of aligning water supply infrastructure with both hydrological potential and demand while ensuring resource sustainability. The study concludes with recommendations, including the extension of infrastructure, the implementation of Managed Aquifer Recharge (MAR) systems, and the creation of a centralized GIS-based decision support system for equitable and climate-resilient water planning. By combining satellite data, modeling, and demographic analytics, the proposed framework provides a replicable approach to strengthen water governance in data-scarce river basins.