Integrating social vulnerability to flood risk assessment in Metro Manila

Abstract

This study applied the interaction of social vulnerability and hazard to assess flood risk in three urbanized areas within the Pasig-Marikina-Laguna-Lake catchment: Manila, Marikina, and Parañaque in Metro Manila, Philippines. This study examined risk patterns across different flood return periods (5, 50, and 100 years) in these urban river environments and provided both city-wide and localized risk assessments. The social vulnerability to flood index (SVFI) was calculated using socioeconomic indicators, while the hazard index was derived from flood depth categories. Results show that city-level risk indices are low to moderate, with Marikina consistently having the highest risk, followed by Manila and Parañaque. However, localized assessments reveal high-risk areas within cities, with Manila being the most vulnerable to frequent floods (5-year return period) and Marikina to less frequent but extreme events (50- and 100-year return periods). Parañaque maintains the lowest risk profile across all scenarios. This study highlights the importance of considering both citywide trends and localized high-risk areas in flood risk management. It provides valuable insights for disaster management planners and policymakers, enabling the development of targeted strategies for sustainable urban river management and flood risk reduction in rapidly urbanizing river systems. The methodology presented applies to other urban areas that face similar flood risks.

Keywords

flood risk management / hazard index / Metro Manila / social vulnerability

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