FLOOD PLAIN MAPPING USING CIS III LOWER PART OF CHINDWIN RIVER IN MYANMAR

Abstract

Flood is one of the natural disasters which occur in Myanmar every year. Floods generally occur during the southwest monsoon (June to October), when the westerly depression system and the low latitude tropical cyclone system may cause the macroscopic rainstorm. These floods had caused -appreciable damage to livestock, agricultural crops, roads, bridges and buildings etc. It is evident 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 investigation proposes to estimate the flood quantiles of different return periods using L-moment, to predict the daily water level for 1 day ahead using ANN and to develop the digital elevation model. Basic aim of this effort is to identify the flood plain maps of different return periods. In this study, the daily stage, annual peak' flow and rainfall from six gauging stations of Chindwin basin and topographic maps in scales of 1: 63, 360 with 50 ft contour interval for the lower part of Chindwin basin are collected. In this study, softwares such as R2V for digitization of topographic maps, ArcGIS for DEM creation, HEC-RAS for hydraulic modeling and HEC-GeoRAS for flood plain mapping have been used. This study shows that combination of modern tools and techniques (mentioned above) yields a.efficient and accurate methodology for flood forecasting (using ANN), flood quantile estimation and HEC-RAS output in GIS format, is a innovative method for flood plain mapping.