Multi-GCMs approach for assessing climate change impact on water resources in Thailand

Abstract

Climate-driven floods have severely affected Thailand’s economy in the recent past, indicating the necessity of better water management plans at both watershed and national scale. Corresponding to this, the present paper attempts to address the potential implications of future climate on hydrology at seasonal scale in Thailand. Nine Hydrological Response Units (HRUs) were identified from the whole country based on the similarity in land use and soil properties which were further modelled by HEC-HMS for water resources estimation under climate change. The future precipitation data for SRES A2 and B2 scenarios were derived from five commonly used Global Climate Models (GCMs). Simulation for the dry season implies that the water resources are expected to change from − 17.43 to 54.74%, whereas for the wet season, the projection is expected to vary from − 7.47 to 48.29% relative to the baseline period (1991–2000) irrespective of the scenarios and time windows considered. The uncertainty in water availability projection ranges from 0.78 to 15.78% and 1.87 to 22.35% for the corresponding seasons. At national scale, the decadal water availability ranges from − 5.38 to 13.96% and 0.71 to 30.27% for dry and wet seasons respectively when compared to the baseline period. Similarly, the uncertainty associated ranges from 1.03 to 7.78% and 2.89 to 13.47% for the corresponding seasons. The outcomes of the study emphasize on increased flow both in the HRUs and at the national level and will be helpful in formulating better water management plans to counteract the possible floods in the future.