GIS-Based Flood Susceptibility Assessment of Cabanatuan City, Nueva Ecija, Philippines

Flooding is a recurrent hazard in Cabanatuan City, Philippines, within the Pampanga River basin. This study assessed flood susceptibility using GIS mapping across all 89 barangays. Flood susceptibility was assessed using weighted GIS-based analysis of elevation, slope, land use/land cover, and proximity to drainage networks. Rainfall was discussed qualitatively as a triggering condition but was excluded from the weighted FSI computation due to the absence of spatially distributed rainfall data. Rainfall is treated only as a triggering condition due to citywide data limitations; this limits the model’s ability to represent temporal flood variability. A Flood Susceptibility Index (FSI) was calculated using normalized weights: Distance to River (29%), Elevation (26%), Slope (23%), and Land Use (22%). Results classified 24 barangays (27.0%) as High Susceptibility, 47 (52.8%) as Moderate, and 18 (20.2%) as Low. Valdefuente recorded the highest FSI (2.51) due to developed land use and river proximity within 300 meters. Kalikid Norte, Macatbong, and Patalac recorded the lowest FSI (1.45) due to steeper slopes and agricultural land use. Spatial trend analysis revealed a west-to-east gradient of decreasing susceptibility. Findings show general agreement with documented flood-prone areas. Limitation: The susceptibility map has not been quantitatively validated and is a preliminary assessment. This study provides a replicable framework to guide CDRRMO and LGU in flood mitigation planning.