Impact of climate change on hydrological drought over a coastal river basin in Vietnam

Minh Tue Vu, Ngoc duong Vo, Philippe Gourbesville, Srivatsan Vijayaraghavan, Shie-Yui Liong

Tuesday 30 june 2015

16:45 - 17:00h at North America (level 0)

Themes: (T) Extreme events, natural variability and climate change, (ST) Hydrological extremes: floods and droughts

Parallel session: 7I. Extreme events - Flood Drought

Climate Change is continuing at an unprecedented rate and the latest Inter-governmental Panel on Climate Change (IPCC), Assessment report states that significant changes in rainfall patterns and increased global sea-level rise may be expected by 2100 with a strong emphasis to human-induced forcing, affecting many regions including Southeast Asia. Most of the economically weaker countries in Southeast Asia are highly vulnerable and are in need of both scientific expertise and the economic means to combat climate change. In this context, this study focuses on the hydrological drought situation under current and future climate over a coastal catchment in the centre of Vietnam. This Vu Gia – Thu Bon river basin has been known prone to annual flood and drought and the economy is largely dependent on rice production. The meteorological and hydrological drought is assessed by applying two drought indices: Standardized Precipitation Index and Standardized Runoff Index. In order to assess the hydrological flow over the coastal region, the MIKE-SHE model has been calibrated and validated for a 20 year period 1991-2010. Future climate was assessed using the Regional Climate Model Weather Research and Forecasting that was used to dynamically downscale the Global Climate Model CCSM. The outputs from these climate simulations are used for this hydrological impacts study. The results suggest that despite hotter and wetter future climate, the study region is likely to experience more severe to extreme drought.