Assessment of future climate and vegetation canopy change impacts on hydrological behavior of Chungju dam watershed using SWAT model

The impact on hydrological components including evapotranspiration, soil moisture content, groundwater recharge, and dam inflow by the future potential climate and vegetation canopy changes was assessed for a dam watershed using Soil and Water Assessment Tool (SWAT) model. The SWAT model was calibrated and verified using 9 years (1997–2006) and another 7 years (1990–1996) daily dam inflow data, respectively for a 6,585.1 km2 dam watershed located in the mountainous northeastern part of South Korea. The second generation coupled global climate model (CGCM2) data of Canadian Centre for Climate modelling and analysis (CCCma) from two Special Reports on Emissions Scenarios (SRES) climate change scenarios (A2 and B2) of the Intergovernmental Panel on Climate Change (IPCC) were adopted. The future vegetation canopy was developed by the nonlinear regression between monthly Leaf Area Index (LAI) from Terra MODIS (Moderate Resolution Imaging Spectroradiometer) images and monthly mean temperature of 7 years (2000–2006) data. The future prediction results with A2 and B2 scenarios showed that the maximum changes in annual dam inflow were predicted to be −18.2% in 2090s A2 scenario compared to 2000 baseline data. The future seasonal maximum dam inflow changes appeared in fall period to be −31.0% for the A2 scenario. From the contribution analysis of climate change and vegetation canopy for the overall future predicted results, the climate change primarily led the future impact on the predicted results. For the future vegetation impact on hydrological components, soil moisture was more sensitive than dam inflow and evapotranspiration.