Envisioning a Sustainable Water Resource Governance in the Sambunotan Watershed: Integrating GIS, Hydrology, Geology, and Water Quality Insights

KEY POINTS ● The Sambunotan Watershed is essential for water supply, agriculture, and biodiversity in northern Dinagat. However, it faces natural and man-made disruptions that include deforestation, mining, unsustainable farming, and climate variability, putting ecosystem services and the community well-being at risk. ● A revised watershed boundary corrected discrepancies in earlier delineations and revealed that the Sambunotan River is not its primary tributary. ● With approximately 70% of the watershed classified as Alienable and Disposable (A&D), 30% as timberland, and no protected areas, combined with mining tenements covering more than 75% of its area, the watershed is highly vulnerable to environmental degradation. ● Hydrological modeling highlighted seasonal water dynamics, with a total baseflow of 71.60 million cubic meters (MCM), while water quality analysis linked land use, particularly tree cover, to improved water parameters, underscoring the need for sustainable land-use practices. ● Key recommendations include designating protected areas or local conservation areas, regulating mining and land use in A&D zones, improving water and sediment monitoring, enhancing reforestation in riparian zones, and renaming the watershed to align governance with its true ecological and hydrological features.