Abstract

This paper investigates the potential impact of climate change on future water availability in Thailand. For this study, entire country was divided into nine Hydrological Response Units (HRUs) and the hydrological modeling was performed by Hydrologic Engineering Center’s Hydrologic Modeling System (HEC-HMS) for each HRU using the future decadal climate data obtained from the Regional Climate Model (RCM) named Providing Regional Climates for Impact Studies (PRECIS) which was further bias corrected by using ratio method for two emission scenarios A2 and B2. The simulation shows that the water availability in the future decades at the different HRUs varies for the dry and wet season. In case of dry season, the coastal HRUs show a decline in water availability in the near future then tending to increase to the similar amount as of current situation in the late part of century. However, in case of wet season all the HRUs shows an increasing trend of water availability in future. Nonetheless, considering the whole country for dry season the water availability is expected to be decreased in the early part of the century followed by an increasing trend by the end of the century relative to current water availability for both scenarios. Similarly a univocal increasing trend of water availability is expected for wet season indicating the possibility increased frequency and intensity of floods.

Keywords: Climate change; HEC-HMS; PRECIS; Water availability; Thailand