Malatgao Integrated Watershed Management based on Water Availability Assessment

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. However, its implementation is often constrained by inadequate hydrological data. This study analyzes water availability in the Malatgao River in Palawan, Philippines, to inform 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 a Flow Duration Curve (FDC), and stakeholder consultations through expert interviews and surveys. The Random Forest model demonstrated good prediction performance (RMSE=0.97; MAE=0.76). Results revealed probable flash floods during high-flow periods, though perennial storage supports sustained baseflow. Experts recommended a combination of nature-based solutions, structural measures, sustainable farming practices, strict land-use regulation, and community participation as Best Management Practices (BMPs) that are well-aligned with the basin’s hydrologic conditions. Broad stakeholder support for these strategies implies a strong potential for successful IWM implementation in the Malatgao Watershed.