Responses of river discharge and sediment load to climate change in the transboundary Mekong River Basin

Climate change is expected to alter streamflow and sediment load in the transboundary Mekong River Basin (MRB), thereby affecting aquatic ecosystem and people's livelihoods. Thus, future decisions on sustainable management of water resources in the basin should take climate change impact into consideration. In this study, the responses of river discharge and sediment (total suspended sediment [TSS]) load to future climate change in the transboundary MRB have been investigated. The Soil and Water Assessment Tool (SWAT) model is used as a simulation tool, which has been carefully calibrated and validated against the observation data in the period of 1982-2005 before applying to evaluate the impact of climate change scenarios for the near-future period of 2016-2040. The climate change scenarios, which are acquired from four different Regional Climate Models (RCMs) downscaled from the Hadley Centre Global Environmental Model version 2-Atmosphere (HadGEM2-AO), are applied in the present study. In regard to the effect of changing climate, the annual river discharge and TSS load are forecasted to rise from 3.35 to 9.13% and from 7.45 to 13.15%, respectively. Generally, the TSS loading projection varies larger than the streamflow projection concerning changing climate. The findings here are also agreed with the conclusions of previous investigations on the future impacts of changing climate in the MRB.