Evaluating Surface Water-groundwater Interactions in Consequence of Changes in Climate and Groundwater Extraction

This study explores spatio-temporal patterns of surface water-groundwater interactions in the Yom and Nan River basins, a vulnerable and essential agricultural region in northern Thailand, under various future climate conditions. The SWAT-MODFLOW model performs the coupled simulation of surface/subsurface hydrological processes in the watershed, with projected climate conditions from the three Global Climate Models (MIROC5, CNRM-CM5, and MPI-ESM-MR) under the minimum and maximum Green House Gas emission scenarios, represented as the RCPs 2.6 and 8.5. The results demonstrate that, in the near future (2026-2045) under the two scenarios, a raised air temperature at 0.5-1.0 degrees C with a 2-16% increment of annual rainfall cause a 7-20% decrease in groundwater recharge from surface water percolation, followed by a 11-21% depletion of groundwater flow to river, while aquifer recharge from the river change negligibly. In the intermediate future (2051-2070) and far future (2076-2095), changes in surface water-groundwater interactions under RCP 2.6 are rather similar to the near future because of insignificant differentiation in climate conditions. Whereas, under RCP 8.5, annual rainfall increases by 26% and produces 4-14% increments of groundwater recharging and groundwater discharge to streamflow, while river seepage increases by 1-18%. These provide key insights into northern Thailand watershed systems to deal with future impacts of climate change on water supply.

Automated summary

This study examines the spatio-temporal patterns of surface water-groundwater interactions in the Yom and Nan River basins in Thailand under different future climate conditions. The results show that increased air temperature and rainfall can lead to decreased groundwater recharge from surface water percolation, as well as reduced groundwater flow to rivers. However, the impact on aquifer recharge from rivers is minimal. The findings provide valuable insights into how future climate change can affect water supply in northern Thailand.