Hydrology and flood probability of the monsoon-dominated Chindwin River in northern Myanmar

Abstract

As the third largest river of Myanmar, the Chindwin River has great importance as a water resource and transport artery. At 113,800 km2 the basin is comparable in size to the Elbe basin in Europe, although with higher rainfall and runoff. During the southwest monsoon high rainfall intensities with spatial and temporal variation causing severe floods are threatening the region. The study aims to analyze the hydrologic aspects of monsoon floods using statistical and frequency analysis. Flood responses vary due to the complex topography and rainfall distribution over the catchment. Time series of annual maximum floods shows no trend of the mean value. The deviation of annual maxima from the respective mean values, however, has increased significantly in recent decades. Flood quantiles are determined for return periods of 2 to 1,000 years using the data covering the period 1966 to 2011. Flood probability analysis shows that the upper and middle parts of the basin have particularly high flood risks. To analyze the change in flood values, the relative differences of flood quantiles in two time phases, 1966–1990 and 1991–2011, with respect to the entire observation period are compared. The expected floods of the latter period are the highest.