Assessment of Future Climate and Land Use Change Impacts on Hydrological Behavior of Dam Watershed Using SWAT-K Model

摘要

The impact on hydrological components viz. evapotranspiration, soil moisture content, groundwater recharge, and dam inflow by the future potential climate and land use change was assessed fora dam watershed using SWAT-K (Soil and Water Assessment Tool-Korea) model. The SWAT-K model was calibrated and verified using 9 years (1997-2006) and another 7 years (1990-1996) daily dam inflow data fora 6,661.6 knf dam watershed located in the middle-eastern part of South Korea. The model was calibrated and verified with RMSE (Root Mean Square Error) and Nash-Sutcliffe efficiency ranging from 1.0 to 2.9 and 0.43 to 0.91 respectively. The CCCma CGCM2 data by two SRES (Special Report on Emissions Scenarios) climate change scenarios (A2 and B2) of the IPCC (Intergovernmental Panel on Climate Change) were adopted, and the future weather data was downscaled by change factor methods using 30 years (1977-2006, baseline period) weather data of 5 meteorological stations. The future land uses were predicted by CA (Cellular Automata)-Markov technique using the time series land use data of 4 Landsat images. The 2090 future land use showed that the forest-evergreen decreased 53,4 % while forest-mixed and forest-deciduous increased 53.2 % and 89.2 % for each area comparing with the 2000 Landsat land use. The future vegetation cover information was prepared by the linear regression between monthly LAI (Leaf Area Index) from Terra MOD IS images and monthly mean temperature of 7 years (2000 -2006) data. The future prediction results showed that the maximum changes in annual dam inflow were predicted to be-11.2% in 2090s A2 scenario compared to 2000 baseline data. The future seasonal maximum dam inflow changes appeared in fall period to be- 22% forA2 scenario. The maximum possible evapotranspiration changes were appeared in 2060s B2 winter period reaching to + 764.5 % while other periods were within + 31 %. According to the future increase of ET, the future maximum A2 and 82 so/7 moisture changes were -24.1 % in 2090s A2 fall period. The future assessment results show a new paradigm for challenging efficient water resources management of a watershed and the increasing water demands under the water resources deficiency in the near future.