Manila Flood Inundation Simulation

Authors: Tuico, Rowell O., Mamatra, Julie Anne Marie R., and Matute, Ma. Kathrina M.

Issue: 2019


Tropical cyclones, known as “bagyo” in the Philippines, are intense weather systems that bring strong winds, heavy rainfall, and large waves. On average, about 100 tropical cyclones form globally per year, with two-thirds strengthening into typhoons and hurricanes. The Western North Pacific Ocean sees the most tropical cyclone genesis at 30%, followed by the East Pacific Ocean at 15% and the Western Atlantic, South and North Indian, and South Pacific Oceans each at 12%. According to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), over 20 storms impact the Philippines annually. This frequent typhoon threat combined with seasonal monsoon rains produces damaging floods. This study aims to simulate potential flood levels during typhoons across vulnerable regions of the Philippines. The simulations incorporate storm data from PAGASA and digital elevation models to estimate rainfall runoff volumes and flood inundation for low-lying areas. The results provide an enhanced visualization of flood risk to improve disaster preparedness and resiliency. The flood projections rely on rainfall volume, storm duration over specific watersheds, and elevation data to model potential flood levels. Further model development with higher resolution data would continue to refine these disaster risk estimates.