The objective of this study is to evaluate Flow-Pollutant load delivery ratio equations developed from rural watershed on main subwatersheds within Juam Lake. Two regression equations for BOD and three equations for T-P were evaluated on Bosung cheon, Dongbok cheon, Songgwang cheon, Naenam cheon, and Sinpyeon cheon. The results show that estimation of BOD delivery ratio using flow-delivery equation is reliable when relative composition of discharge load of pollutant sources of a watershed is similar to those of watershed where the equation developed. On the other hand, application of regression equation for T-P was feasible when the landuse pattern and relative composition of discharge load of pollutant sources of a watershed is similar to those of watershed where the equation developed.

The objective of this study is to provide pollutant loads delivery ratio for flow duration in Oenam-cheon watershed, which is upstream watershed of Juam Lake. To calculate the delivery ratio by flow duration, rating curves and discharge-loads curves using measured data were established, then Flow Duration Curve(FDC) and pollutant loads delivery ratio curves were constructed. The results show that the delivery ratios for BOD5 for abundant flow(Q95), ordinary flow(Q185), low flow(Q275), and drought flow(Q355) were 23.9, 12.7, 7.1, and 2.9%, respectively. The delivery ratios of same flow regime for T-N were 58.4, 31.2, 17.2 and 7.1%, respectively. While, the delivery ratios T-P were 17.3, 7.5, 3.4, and 1.1% respectively. In general, delivery ratio of high flow condition showed higher value due to the influence of nonpoint source pollution. Based on the study results, generalized equations were developed for delivery ratio and discharge per unit area, which could be used for ungaged watershed with similar pollution sources.