Comparing water quality between Korean and Japanese river

Two watersheds with similar area were selected to compare water qualities between Korea and Japan. The one from Korea is called the Yongdam dam watershed in the Geum river basin, and the other from Japan is called the Nakama watershed in the Onga river basin. The 2 water quality stations from Korea and 2 stations from Japan within each watershed were selected and water quality concentration data were collected to determine load durations, respectively. The relationships between discharge and water pollution load on BOD, COD, SS, TN, and TP were derived, and water pollution loads were estimated on a daily basis in each water quality station. And means of LDCs in each country were drawn and compared with each other. Summarizing the estimated daily water pollution loads and the results of LDCs, it was concluded that TMDL showed 1.49 times higher BOD, 1.11 times higher COD, 4.95 times higher SS, 1.43 times higher TN in Korean and the same TP, and 1sup(st) load in LDC showed 1.81 to 6.14 times higher in Korean, and remaining 95sup(th), 185sup(th), 275sup(th), and 285sup(th) loads in LDC showed 1.30 to 15.43 times higher in Japanese. Specific loads were expressed with daily mean in the period of each flow duration interval, and were compared with each other between Korea and Japan, of which results were shown with 1.836-8.063 times higher to Korea in high flows, and with 1.119-8.169 times higher to Japan in other flows except SS, TN values in moist conditions. Comparing an annual sum, BOD load was 1.16 times higher in Korea, COD 1.113 in Korea, SS 4.891 in Korea, TN 1.446 in Korea, and TP was same. Evaluating with 10 year frequency, Korea showed 1.041-2.360 times higher loads than Japan except TP in high flows, Japan 1.175-14.226 times higher than Korea except TN in low flows. Annual sum showed that BOD load was 1.517 times higher in Japan, COD 1.564 in Japan, SS 1.408 in Korea, TN 1.008 in Korea, and TP 2.383 in Japan. From the above result, it was concluded that Korean river was getting more water pollution loads than Japanese river in high flow interval, but in other flow interval was higher to Japan in general.