Flood Risk at Various Stages of Catbalogan Sky City Project Development
The effects of climate change on low-lying communities discouraged cities to reclaim seas for urban expansion. The storm surge that has occurred during the onslaught of Typhoon Haiyan in some parts of the Visayas in the Philippines discouraged the City of Catbalogan from pursuing expansion through reclamation. Instead, the local government proposed a Sky City project which intends to develop the hills surrounding the city as the new growth area. However, the development will cause various problems, one of which is the increased runoff due to change in ground cover. The paper aimed to calculate the increased runoff at various stages of development which will lead to flooding in the old city. Data from 36 scenarios (9 rainfall intensity and 4 stages of the project) using Hydrologic Modeling System (HEC-HMS 4.1) of the US Corps of Engineers, reveals that areas along the river will swell at rains smaller than 10mm in 1 hour. While potential risk on other parts of the city remains almost the same. There is a need to implement mitigating measures against the expected increase in runoff volume before the Sky City project development starts.