Flood control simulation for disaster management in Wai Batu Merah River Basin

Abstract

Ambon City, located in Maluku Island, experiences flood disaster every year. It has been considered that the flood in this city occurs more often compared to the other city in the same island. One of the river that is related to the flood occurrence in Ambon City is Wai Batu Merah River. This study aims to find appropriate structural measurement by using modelling simulation to control flood disaster in Wai Batu Merah River Basin. The modelling used HEC-RAS 5.0.7 software for coupled 1D and 2D hydraulic simulation. Flood discharge was calibrated by applying flood event in 2013. The SCS method was selected to generate flood hydrograph by using synthetic method. The records of water depth in the flood event were compared to the hydraulic model results and it showed good agreement. Based on the model, flood control scenarios i.e. normalization and dike were exercised for 25 year return period as required by government regulation. The combination of both scenarios can manage flood in Wai Batu Merah River Basin effectively. However it might need high cost to construct the structures. Therefore, it is necessary to have priority between the scenarios.