Impact of Climate Change on Streamflow, Evapotranspiration, and Sediment Yield in the Mekong River Basin

The aim of this study is to examine the impacts of climate change on water resources in the Mekong River Basin (MRB), which has a direct impact on livelihoods and ecosystems. To consider how the MRB can be developed and managed sustainably in the future, an assessment of the impact of climate change on water resources is essential. We investigated the impact of climate change extremes (very wet, normal, and very dry based on precipitation and hot, normal, and cold based on temperature) on streamflow, evapotranspiration, and sediment yield. Our study analyzed the changes in 53 sub-basins of MRB using the Soil and Water Assessment Tool Model (SWAT). The maximum increase (30.06%) in precipitation was observed using CSIRO-Mk3-6-0 (very wet category) and the maximum reduction (-10.27%) was observed using IPSL-CM5A-MR (hot category). Based on the same GCM (CSIRO-Mk3-6-0), a maximum increase of 39.44 % was observed in streamflow and 140.59 % in sediment yield. With IPSL-CM5A-MR and MIROC-ESMCHEM GCMs, maximum declines in streamflow (-18.80%) and sediment yield (-53.87%) were observed, respectively. In addition, we observed the maximum and minimum changes in ET using MIROC5 (normal temperature) and GFDL-ESM2M (cold temperature), respectively. Through our results, decision makers in the MRB can benefit from sub-basin-wise results of streamflow, evapotranspiration, and sediment yield.

Key words: Mekong River Basin (MRB), climate change, water resource, Soil and Water Assessment Tool Model (SWAT)