Geospatial-based Vulnerability Assessment of an Urban Watershed

Abstract

Abstract Watersheds and other related ecosystems have played a significant role in providing various functions that are vital to society. However, due to the increasing problems on climate change, these watersheds are now subjected to several environmental hazards posing many concerns that affect its management and sustainability. Thus, it is imperative to determine the vulnerable regions in these landscapes to identify priority areas that may require immediate intervention. This paper aims to determine the vulnerability of watersheds using a geospatial-based environmental vulnerability index called the Geospatial-based Regional Environmental Vulnerability Index for Ecosystems and Watersheds (GeoREVIEW). This approach is, then, utilized to assess the vulnerability of La Mesa Watershed (LMW), a vital carbon sink and an important source of domestic water supply in Metro Manila. Based on the assessment, LMW received an overall vulnerability point (OVP) of 62.52 that classifies it as’at risk’ level. A vulnerability map ranging from 2.86 to 3.52 was also generated from the process. It was found that around 69.7% of the watershed have vulnerability scales of >3.0. In addition, priority areas were determined using an evaluation matrix and results showed that around 8.4% (193.4 ha) of LMW have high to very high priority levels. All these information are very indispensable and can be used to address management issues, such as resource prioritization and optimization. In addition, these can be utilized to sustainably manage the watershed particularly on the provision of quality water for domestic use of several cities in the national capital region as well as its neighbouring provinces.