A Rapid Screening Method for Ecological Risks Posed by Different Land Use Intensities: Case Study of Marikina City’s River System

Land use plays an important role in environmental and sustainability research because of its potential contribution to ecosystem protection or degradation. However, most risk maps used in comprehensive land use planning only identify areas at risk, for example, to various geophysical or climate- and weather-related hazards. It would also be useful to identify land areas that pose a risk to ecological systems. In this study, a simplified method adapted from the source-habitat approach and the relative risk model was used to explore the potential ecological risk of exposure to water pollutants posed by land uses on the river system in Marikina City. Geographic Information Systems (GIS) was used to relate the type and intensity of land use (the stressor/source) to the quality of the Marikina River system (the receptor/habitat) via proximity and drainage connections to the river system. The spatial processing of the risk components showed that overall, the Mixed-use Zones followed by the Socialized Settlement Zones posed the highest ecological risk to Marikina’s river system. The method developed can provide stakeholders with a rapid screening approach to identify zones needing more comprehensive analysis in the process of land use planning and developing management policies that can help protect the river ecosystem.