Modeling Discharge to Assess the Influence of Increased Impervious Areas in Cagayan De Oro City, Philippines

• Main Author: Fernandez, Alecz Gabrielle
• Format: text
• Published: Archīum Ateneo 2021
• Subjects: n/a
• Online Access: https://archium.ateneo.edu/theses-dissertations/506
• Institution: Ateneo De Manila University

Many studies have shown that the increase of impervious areas alter the natural hydrology of an area. This increase resulted to heightened peak discharges as well as more flood volume. This often results to more destructive flooding events. Such destructive flooding events have occurred in Cagayan de Oro City in the Philippines. These events have resulted to property damages and loss of lives. Due to the pressures of an increasing population, rapid urbanization is expected in the city. The increase of impervious areas may aggravate the flooding. This study aimed to investigate the influence of the increase of impervious areas on the discharge and extent of flooding in the city. The openLISEM model was used to simulate the flood where the land cover from 2003, 2010, 2015, the 2000 Comprehensive Land Use Plan (CLUP), and the 2022 CLUP were considered. These flood simulations were performed with light, moderate, heavy rainfall as defined by PAGASA as well as the rainfall during Tropical Storm Sendong (international name Washi), Typhoon Pablo (international name Bopha), and Typhoon Vinta (international name Tembin). The land cover analysis showed that land cover of Cagayan de Oro City has not had major changes since 2003. Because of this, the hydrologic response in the area has not been altered. The results showed relatively the same peak discharges and the same extent of flood in all land scenarios for a particular rainfall scenario. However, considering an increase of impervious areas in the city, the peak discharge increased. This was observed in the results of the simulations with the 2000 and 2022 CLUPs. This study can provide more information to the local government officials and guide them to make more evidence-based plans and policies for the city’s flood risk mitigation and prevention.