Water balance components of a bare soil with slope varying from 5% to 30% in Chuncheon, South Korea, were simulated using the E-DiGOR model, which proposed an interactive way to quantify runoff, drainage, soil water storage, and evaporation. | Turkish Journal of Agriculture and Forestry Research Article Turk J Agric For (2014) 38: 80-90 © TÜBİTAK doi: Long-term water balance of a bare soil with slope in Chuncheon, South Korea Mehmet AYDIN*, Yeong-Sang JUNG, Jae E. YANG, Hyun-il LEE Department of Biological Environment, Kangwon National University, Chuncheon, South Korea Received: Accepted: Published Online: Printed: Abstract: Water balance components of a bare soil with slope varying from 5% to 30% in Chuncheon, South Korea, were simulated using the E-DiGOR model, which proposed an interactive way to quantify runoff, drainage, soil water storage, and evaporation. Daily computations were carried out during the period of 1980 to 2009 for the identified soil-topography-climate combination. A strong correlation between measured pan evaporation and calculated potential soil evaporation was observed (R2 = , P < ) based on the monthly data of the past 30 years (hereafter ‘long-term’). When examining long-term dynamics of simulated soil evaporation, monthly mean potential and actual soil evaporations ranged from and mm in December to and mm in June and July, respectively. The ratio of actual to potential soil evaporation (Ea/Ep) had a close linkage with soil water content. The higher the soil water amount, the greater the Ea/Ep ratio was. A nonlinear relationship between rainfall and surface runoff was obtained at a given slope. Excess surface runoff and subsurface flow (percolation + interflow) occurred throughout the rainy months from July to September, with peaks in July. The ratio of direct surface runoff to rainfall increased with the natural logarithm of slope. The long-term mean annual direct surface runoff and subsurface flow at the maximum slope were and mm, respectively. Furthermore, mean annual surface runoff from the slope of 30% was approximately 2
