Sub-catchment Prioritization in a Tropical Watershed for Stream Health Improvement and Low Impact Development Application Using Multi-Criteria Decision Analysis: A Case in Palo, Leyte, Philippines

The adverse impacts on streams due to rapid development have prompted the development of sustainable urban drainage design such as low impact development (LID). Still, the prioritization of its application remains a challenge. This research aims to create a sub-catchment prioritization scale in a tropical watershed using Multi Criteria Decision Analysis (MCDA) for stream health improvement and LID application in Palo, Leyte, Philippines. Ten sub-criteria under three clusters were assessed under the physical, hydrologic-quantity, and hydrologic-quality groups based on site conditions and benefits of LID. Results from each cluster show different priorities depending on location and parameter: the upstream-midstream is characterized by high slopes and sediment accumulation (5,014 g), while midstream-downstream has high runoff (20.03 mm) and heavy metal concentrations and low infiltration (2.21 mm). The two weight scenarios and performance assessment dictate that the downstream areas should be prioritized, although the initial treatment at the upstream can also prevent degradation downstream.