Flood hazard assessment of the central business district of Tarlac City

• Main Authors: Botor, James Bryan B., Javellana, Matthew T., Robles, Joshua Rae F., Villasenor, Alyssa Lorainne A.
• Format: text
• Language: English
• Published: Animo Repository 2016
• Subjects: Flood forecasting > Philippines > Tarlac City; Flood damage prevention > Philippines > Tarlac City; Floods > Economic aspects > Philippines > Tarlac City
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/7723
• Institution: De La Salle University

Flood disasters are by far, the most catastrophic natural threat to affect the Philippines. Flooding can have a severe negative impact on the economic progress of a city, thus making it necessary to invest in flood mitigation. The central business district (CBD) of a city is often regarded as the area with the highest economic potential and value. The CBD of Tarlac City, Tarlac Province remains a highly flood prone urban area. Quantifying the flood hazard will aid the governing bodies and stakeholders in making informed decisions and in developing flood mitigation strategies. The researchers aimed to develop various rainfall return-period flood hazard maps to provide information on the magnitude and spatial variation of flooding hazard based on depth and velocity. The researchers utilized LiDAR elevation data, specifically, a digital terrain model (DTM) and a digital surface model (DSM) of Tarlac Province obtained from University of the Philippines - Department of Science and Technology (UP-DOST). Using the HEC GeoHMS toolbox in ArcGIS, the researchers delineated the sub-basins and isolated the sub-basin containing the CBD. The boundaries of the CBD basin were then used to extract the same area in the DSM, and the surface model was used to determine flow and flood inundation. The model was developed using the software FLO-2D, utilizing parameters relevant to surface flow and hazard distribution such as land use, return period hyetographs, and curve number values which were obtained from Peyra et al. Study on the Effects of Land Use Changes to the Urban Hydrology of Tarlac City, Tarlac. It was found that the drainage path of the study area flowed in two directions with the eastern direction. It was also found that the behavior of hazard in the CBD of Tarlac City, in terms of its spatial distribution and coverage, varies with topography, land cover, flow direction and intensity of rainfall. Areal extent under high hazard increased in downstream catchments with increases in intensity of the rainfall and upstream catchments appear to maintain the same extent regardless of increases in intensity of rainfall.