A FLOOD SUSCEPTIBILITY ANALYSIS OF THE DAVAO RIVER WATERSHED, DAVAO CITY, PHILIPPINES

share:

print:

Current issue: Volume 25, No. 1 (2025)

A FLOOD SUSCEPTIBILITY ANALYSIS OF THE DAVAO RIVER WATERSHED, DAVAO CITY, PHILIPPINES

Jason Ben R. Paragamac*, Rylle G. Añuber

DOI: https://doi.org/10.59893/abud.25(1).008

Paragamac J.B.R., Añuber R.G. 2025. A flood susceptibility analysis of the Davao River Watershed, Davao City, Philippines. Acta Biol. Univ. Daugavp., 2025(1): 121-140.

Abstract

This study aimed to assess the susceptibility to flood of Davao River Watershed by analyzing geospatial and hydrological characteristics. It employs Geographic Information System (GIS) and Remote Sensing (RS) techniques to quantify flood susceptibilities based on the parameters evaluated. Data has revealed 63.40% of the watershed is classified as very low drainage density resulting in slower water movement. In terms of elevation, 37.79% is considered highly elevated with estimated elevation of 1080-1440 means above sea level indicating lower susceptibility. The watershed areas dominated by forest with 75.93% with rainfall distribution patterns of 34.80% receiving an estimated rainfall of 3000 mm classified as highly susceptible. The area has lower computed TWI which covers the 51.91% indicating that water is less likely to accumulate, most likely to related to its gentle slopes classified as 3-8% which facilitates good drainage. Although, vegetation cover is classified as low which increases the susceptibility to flood, which potentially accelerated due to its soil type which is Camasan Clay accounts the 63.52% of the watershed. Its proximity to streams can influence the likelihood of flood risks covering 31% of the watershed located 800-1000 away from the nearby stream. AHP results have determined slope with weight of 20.87 as the most influential variable among geomorphological and hydrological parameters examined. Even with these parameters, the Davao River Watershed is categorized as moderately susceptibly to flood indicating vulnerabilities considering extreme rainfall events and land use change dynamics. 

Keywords: Flood Susceptibility, GIS, Watershed, Remote Sensing, Philippines.

*Corresponding author: Jason Ben R. Paragamac. Professional Schools, University of Mindanao, 8000, Davao City, Philippines-College of Environmental Studies, Marinduque State University, 4900, Boac, Philippines. Email: jasonben_paragamac@umindanao.edu.ph

Rylle G. Añuber. Environmental Studies Department, University of Mindanao, 8000, Davao City, Philippines