Assessment of Climate Change Impact on Storage Behavior of Chungju and the Regulation Dams Using SWAT Model

Abstract

This study is to evaluate the climate change impact on future storage behavior of Chungju dam(2,750*10 6 m 3 ) and the regulation dam(30*10 6 m 3 ) using SWAT(Soil Water Assessment Tool) model. Using 9 years data(2002～2010), the SWAT was calibrated and validated for streamflow at three locations with 0.73 average Nash-Sutcliffe model Efficiency(NSE) and for two reservoir water levels with 0.86 NSE respectively. For future evaluation, the HadCM3 of GCMs (General Circulation Models) data by scenarios of SRES (Special Report on Emission Scenarios) A2 and B1 of the IPCC (Intergovernmental Panel on Climate Change) were adopted. The monthly temperature and precipitation data (2007～2099) were spatially corrected using 30 years (1977～2006, baseline period) of ground measured data through bias-correction, and temporally downscaled by Change Factor (CF) statistical method. For two periods; 2040s (2031～2050), 2080s (2071～2099), the future annual temperature were predicted to change +0.9℃ in 2040s and +4.0℃ in 2080s, and annual precipitation increased 9.6% in 2040s and 20.7% in 2080s respectively. The future watershed evapotranspiration increased up to 15.3% and the soil moisture decreased maximum 2.8% compared to baseline (2002～2010) condition. Under the future dam release condition of 9 years average (2002～2010) for each dam, the yearly dam inflow increased maximum 21.1% for most period except autumn. By the decrease of dam inflow in future autumn, the future dam storage could not recover to the full water level at the end of the year by the present dam release pattern. For the future flood and drought years, the temporal variation of dam storage became more unstable as it needs careful downward and upward management of dam storage respectively. Thus it is necessary to adjust the dam release pattern for climate change adaptation.

Uncertainty of Hydro-meteorological Predictions Due to Climate Change in the Republic of Korea

“…As highlighted by Velázquez et al (2013), the results of this study also show that the selection of the GCM strongly affects the impacts of climate change on runoff. This study covers a wide range of plausible climate change(12 GCMs) and therefore our results differ significantly from those of previous studies in which less GCMs, greenhouse gas concentration projectile and hydrological models are considered (Jeong et al, 2013;Kim et al, 2013b;Sohn et al, 2014).…”

“…The study showed significant uncertainty in runoff even under the same climate change simulations due to the different hydrological and ET models. Jeong et al (2013) used one GCM and two Special Report on Emissions Scenarios (SRES) scenarios and predicted modest increases in runoff of 2.2% to 4.8% in the Chungju Basin with changes in potential evapotranspiration(ET) and soil moisture of +7.6 to +15.3% and -2.1% to -1.8%, respectively, for the 2080s. In another study, Sohn et al (2014) used 3 GCMs and one SRES scenario and reported changes in runoff from -35% to +40% by the 2080s in Korea.…”

Assessment of Water Supply Stability for Drought-Vulnerable Boryeong Multipurpose Dam in South Korea Using Future Dry Climate Change Scenarios

“…The Coupled Model Inter-comparison Project 5 (CMIP5) climate models have been used in South Korea because they consider Asian-Australian monsoon climate factor [10]. Many studies have studied the climate change impact on future dam inflow from watershed [11][12][13][14][15]. Studies of dam water supply satisfying water demands under future dam inflow and release conditions are necessary.…”