Journal of Korean Society of Agricultural Engineers ISSN:1738-3692(Print) 2093-7709(Online) 한국농공학회논문집

The objective of this paper is to study the discharge characteristics of pollutant loads in small watershed according to probability rainfall using the Hydrologic Simulation Program-Fortran (WinHSPF). The subwatershed of Gosam reservoir watershed in Gyeonggido province was simulated and the probability rainfall of study area was estimated by recurrence interval and duration. The probability rainfalls are 156.5, 205.9 and 277.4 mm for 6 hrs, 12 hrs and 24 hrs in 10 year frequency, and each probability rainfalls is distributed by Huff's 4th quantiles method and applied to HSPF. The pollutant loads were high for initial rainfall. The concentrations of TN, TP and BOD were high as rainfall duration is shorter and rainfall intensity is higher.