Assessment of flood hazards in the municipality of Pulilan, Bulacan

The Philippines experiences flooding regularly. As a way to address flooding in the country, this study modelled the area of Pulilan, a municipality in the province of Bulacan and simulated rainfall of 25 and 50-year return periods. This study incorporates different features present in the area of study such as soil types, elevation, and use as well as other features in its two-dimensional flood inundation models. The study determined the velocity, flow depth, and hazard level exposure of the area being considered. To simulate rainfall and analyze the results of the simulation, various computer programs were used. The main program used for the simulation of rainfall is FLO-2D while the other programs were instrumental in providing the data required in FLO-2D as well as in analyzing the result and in producing the final output. After the simulation, results showed that for the 25-year return period 247,541 out of 277,633 grids or about 89% of the area experienced a flow depth of 0.5 meters or less. The only areas where depth is high are in the northern portion of Apalit and the area near the Angat river. As for the 50-year return period, 86% of the area experienced a flow depth of 0.5 meters or less. For both the return periods majority of the area experienced a flow velocity of less than 0.5m/s. Majority of the area is exposed to a low level of flood hazard