PERTANIKA JOURNAL OF SCIENCE AND TECHNOLOGY

As urban development has progressed, the demand for reliable water supply in Butuan City has increased significantly. However, due to limited water suppliers, the availability of sanitary water could be more inconsistent. Furthermore, the region has experienced heightened occurrences and intensified magnitudes of floods and droughts because of the influence of climate change. Consequently, ensuring an adequate water supply to augment the needs of the growing population has become a pressing concern. Thus, this study developed a hydrological model utilizing the Geographic Information System (GIS) and the Soil and Water Assessment Tool (SWAT) to assess the water yield of the Taguibo River Watershed Forest Reserve. The model was calibrated and validated using monthly average observed discharge data from 2012 to 2013 and 2010 to 2011. The validation phase demonstrated a strong correlation between the model-simulated and actual values, with R2 = 0.87, NSI = 0.73, and PBIAS= –19%, which revealed the satisfactory performance of the model. These findings underscore the effectiveness of integrating the GIS environment and SWAT model for evaluating watershed hydrology and estimating water yield. Overall, this study showcases the potential of GIS and the SWAT model in comprehensively examining the hydrological aspects of watersheds and providing valuable insights into water yield calculations.

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