Impact assessment of climate change on groundwater and vulnerability to drought of areas in Eastern Thailand

Apart from being an important natural water resource, groundwater serves as an alternative source of water supply during natural droughts. Groundwater nevertheless has been increasingly threatened by urbanization, industrialization, seasonal climate variability, and climate change. One of the long-term adverse impacts of climate change is an irreversible change in the precipitation intensity and pattern and subsequently a fluctuation in groundwater recharge and hence subsurface storage. In Thailand especially the eastern region of the country where droughts are perennial, reduced precipitation contributes to shortages of water supply in many agricultural areas and industrial estates in the region. The aims of this research are to identify hotspots and prioritize zones presently threatened by persistent droughts and whose subsurface systems are susceptible and vulnerable to climate change. Thus, exposure index is defined by the change of future rainfall from a GCM model, sensitivity index is assessed by a modified DRASTIC technique, and the adaptive capacity in this region is associated with the current occurrence of seasonal droughts. The exposure, sensitivity, and adaptive capacity factors are combined and ranked through the straightforward overlay matrix technique. The results are presented in the form of hazard, impact and vulnerability maps with hotspots and are useful for better groundwater management and planning as well as policy decision-making.