Engineering and Applied Science Research (Jul 2022)
Assessment of hydrologic variations under climate change scenarios using fully-distributed hydrological model in Huai Luang Watershed, Thailand
Abstract
Huai Luang Watershed is mostly covered by agriculture area and the most population work on farm. The water is an essential factor to support communities in the watershed. Recently in Huai Luang watershed has faced serious problems on water resources such as drought and flood event. Water is a medium that is very vulnerable to the impact of climate changes. Therefore, the objective of the research was to evaluate the effect of climate changes on hydrologic variation in Huai Luang Watershed. This research utilized MIKE SHE for fully distributed hydrological model and coupled with MIKE 11 to model water cycle in watershed. This study used observed streamflow data from Kh.103 station for calibration and validation model. The models were calibrated from the period of 1 January 2004 to 31 December 2006 and validated 1 January 2011 to 31 December 2013. The calibration and validation results indicated agreement between observed and simulated data. The R2, NSE, PBIAS, and RSR values of calibration of daily streamflow were 0.60, 0.53, 5.34, and 0.69 respectively. Meanwhile validation period resulted better performance (R2 = 0.70, NSE = 0.68, PBIAS = -4.13, and RSR = 0.57) than calibration. After Model was developed, then the impacts of climate changes on the watershed response were evaluated using MIKE SHE Model in order to determine the quantities of water resources in 30 years past (1986-2015) and 30 years (2021-2050) later. Eventually, the results showed that the annual actual evapotranspiration has decreased significantly. The increase of overland flow quantity in future projection was tied by the decrease of actual evapotranspiration. Meanwhile, water in unsaturated and saturated zone of historic and future period were not significant changes. It can be safely said that climate changes in watershed do not significantly influence water resources in unsaturated and saturated zone.
