To present water quality management on Seomjingang Multipurpose Dam reservoir, it was investigated to water quality of dam reservoir and watershed Upstream water. quality changed every month at normal flow season for three years from 1998 to 2000 Espe...
To present water quality management on Seomjingang Multipurpose Dam reservoir, it was investigated to water quality of dam reservoir and watershed Upstream water. quality changed every month at normal flow season for three years from 1998 to 2000 Especially the highest water quality concentration was occurred at Yongsan site during normal flow period where it has been more polluted by population and livestock than other sites. Based on the water quality data, the average concentration during rainy period was higher than that of non-rainy period: BOD was 1.2-1.4 times, COD 1.2~l.7 times, SS 2.6-5.4 times, T-N 2.3~3.0 times, and T-P 2.4-7.5 times, respectively. As the concentration of TN on dam reservior showed more than 1.5mg/ℓ for three years, it is necessary to management of N sources on watershed. Moreover the higher concentration of TP on dam reservior showed upper area of dam reservoir like Hinbawi and Ipseok site where it is shallow and near from upper stream at rainy period, it is evaluated that TP affected to inflow of upper stream According to the result of water quality data on Dam reservoir, trophic state evaluated eutrophic and mesotrophic state though it slightly change on time and criterion. The simulation of water quality on Seomjingang Multipurpose Dam reservoir was performed to using physical and water quality data. According to simulation result by pollutant load reduction, water quality of reservoir was not improved suddenly. But this state continue for many years, it surely appear that water quality improved obviously. It is evaluated that Imsilchon basin need wastewater trentment facility to improve water quality on dam reservoir first of all and water quality shows more improved than the other basins to using same cost. From this result, this study proposed optimal site to construction of wastewater treatment facility and also calculated the cost of construction at subbasin.