A hydrodynamic modelling of proposed dams in reducing flood hazard in Kelantan Catchment

Abstract

Flood is natural disaster that can cause damage and death. The flood that hit Kelantan in 2014 was the worst flood in Malaysian history. Although the disaster could not be avoided, awareness and preparedness could have helped to reduce the impact. Kuala Krai located at the downstream area in Kelantan catchment is the most affected due to the 2014 floods. The confluence of Lebir and Galas rivers into Kelantan river has led to the increase of flood magnitude to the downstream area. Therefore, Kemubu dam and Lebir dam, located along Galas river and Lebir river, respectively, have been proposed by the Kelantan authority to reduce the flood hazard. In this paper, a hydrodynamic modelling study is carried out, which is coupled of 1D and 2D model to simulate the flood event with and without the proposed dams. The model is developed using a Digital Terrain Model (DTM), which was generated from Airborne LiDAR and SRTM data sources. The hydrograph and water level for 2014 floods event were obtained and was set as an input data for boundary conditions. The modelling results of maximum velocity of 33 m/s and water depth of 19 m were used to generate flood hazard map. The result has found that the proposed dams were able to reduce the flood hazard, particularly at Kuala Krai, Kelantan.