Abstract
A series of hydropower projects have been planned in the Mekong River, and the influences of these developments of water resources and climate change on hydrological cycle are of particular interest to the Mekong riparian countries. In the Lao PDR, there are about 70 hydropower projects and several dams are under construction upstream of the Nam Ngum Dam (NN1). In this study, we explored the combined impacts of climate change and dam constructions on water management of the NN1 and available water resources in the Nam Ngum River. To assess dam operation and hydrological cycle, a distributed water circulation model and a reservoir operation model were applied to the basin. Furthermore, we used the future climate scenarios by the MRI-AGCM3.1S for the assessment of climate change impact. The results of the analysis show that inflows and reservoir storages of the NN1 during rainy seasons will decrease in drought years due to climate change and new dams in future. In addition, water releases for hydropower of the NN1 will increase owing to smoothing effects of flood discharges by the new dams. These results indicate that the consideration of combined impacts of climate change and water resources developments is of importance in projection of water resources in developing regions such as the Mekong River Basin.
