Malatgao integrated watershed management based on water availability assessment Maricar Mahinay- Cris Edward Monjardin
Mapua University
Abstract
Limited access to sufficient water resources hinders sustainable development, particularly in vulnerable regions. Integrated Watershed Management (IWM) is essential for ensuring water security by coordinating land, water, and other natural resources. A key challenge is the lack of accurate hydrological data. This study analyzes water availability in the Malatgao River in Palawan, Philippines, to support IWM strategies. Specifically, it aims to estimate missing streamflow data, characterize the river^s flow regime, propose suitable management strategies, and validate them through stakeholder engagement. Random Forest regression was used to impute missing streamflow values, followed by creating Flow Duration Curve (FDC), expert consultations, and surveys. The Random Forest model demonstrated good prediction performance (RMSE=0.97- MAE=0.9). Results revealed probable flash floods during high flows, though perennial storage supports sustained baseflow. Experts recommended nature-based solutions-reforestation and Assisted Natural Regeneration (ANR), riparian buffers, streambank stabilization, and slope protection using coconut coir mats. Structural measures such as Sabo dams, dikes, and rainwater harvesting were also suggested. Soil and water conservation practices like contour plowing, terracing, Alternate Wetting and Drying (AWD) for irrigation were considered effective. Regulation of quarrying and slash-and-burn agriculture is also crucial. Broad stakeholder support implies strong potential for successful IWM implementation in the Malatgao Watershed
Keywords: integrated watershed management- flow duration curve- random forest
