Flood forecasting for the lower mekong basin

Abstract

This project was conducted to develop a 2-dimensional (2D) hydrodynamic model based on TELEMAC-2D for the flood simulation of the river from Kratie to Kampong Cham, a part of the Mekong Delta. It aims to investigate the functions of TELEMAC-2D in flood forecasting, as well as determine its feasibility and adequacy in simulating flood in the research area. The TELEMAC-2D model solves the Shallow Water Equations using the finite element method, and with an irregular mesh that covers the floodplain. In this project, the actual flood event in June to November 2001 in the river from Kratie to Kampong Cham was simulated. Simulation results from the TELEMAC-2D model were then compared with the flooded areas captured on MODIS Satellite Images for seven specific days in the Pre, Peak and Post-Flood period. The validation of simulation results was conducted on ArcGIS, where percentage match of flooded cells in both the simulation results and satellite images were determined. It was found that during the Peak Flood period, there was high percentage match in results of above 90%. Hence, the project proved that TELEMAC-2D is indeed feasible in simulating flood events, with high accuracy during the Peak flood period. The accuracy of simulation results is also reliant on availability of information on hydro-meteorological and physiographic data, which is limited for the Mekong River. Hence, several assumptions were required in formulating the 2D hydrodynamic model, which could have affected the accuracy of simulation results. However, the results obtained showed that this project was able to successfully achieve reasonably accurate simulation results for the Peak flood period.