Assessing the Impacts of Climate Change and Reservoir Operation on Saltwater Intrusion in the Vu Gia - Thu Bon River Basin

The Vu Gia - Thu Bon is the fifth largest river basin in Vietnam. During dry periods, this estuary often experiences saltwater intrusion, which has caused adverse impact on irrigation and urban water supply. Especially, saltwater intrusion is expected to change dramatically in the future under the effects of climate change as well as the construction of large dams in the upstream. These variations are investigated in this study using numerical models MIKE 11. Sea level rise and changes in rain of climate change scenarios from Vietnamese Government (2016) are used to analyze the variation of saltwater intrusion. In addition, the effect of reservoir operation was also considered. The results show that the distance of salinity intrusion in the Vu Gia - Thu Bon estuary will increase and move further upstream under the impact of climate change. In the most unfavorable scenario, the salinity boundary of 1‰ can penetrate to 19 km and 28 km from the Cua Han and Cua Dai, respectively, resulting in the limited availability of water of suitable quality for municipal uses.