FLOOD RISK MAPPING

Abstract

Flood is one of the natural disasters which occur in Myanmar every year. Floods generally occur during the southwest monsoon period i.e. from _ June to October; , when the westerly depression system and the low latitude tropical cyclone system causes the rainstorm. These floods had caused appreciable damage to livestock, agricultural crops, roads, bridges and buildings in the past . It is evident from the past record that the problem of river flooding is getting more and more acute due to human intervention in the flood plain at an ever increasing scale. It has been gradually realized that it is more rational to try minimizing the risk and damage involved the floods rather than formulating structural measures for containing the river. The computation of flood water level is needed because this level delineates the flood plain and determines the required height of structures such as bridges and levees. The computation of flood flow rate is also important; first, because the flow rate determines the water level, and second, because the design of any flood storage structure such as a detention pond or reservoir requires an estimate of its inflow hydrograph. It is envisaged to predict the water level using kinematic wave model. Kinematic wave modelling is an important hydraulic engineering practice because it deals with the modeling of movement of flow along the channel over time. Results of channel flow routing provide information regarding to the temporal and spatial distributions of flood wave which is essential for flood warning and protection. In this study, the daily stage, annual peak flow and rainfall from six gauging stations from Chindwin basin have been analyzed.