The inflow into a multi-purpose dam reservoir contains many suspended solids from the upper stream during the rainy season. Concentrations of SS increased to 73.3 mg/l and the TP measurement increased to 0.09 mg/l during the rainy season in 1999. It was discovered that particles less than $10;mu extrm{m}$ in size composed about 50% of the total amount. Some of these particles reduce the reservoir capacity and have an impact on water. In this study, the sediment depth at Daecheong multi-purpose dam was examined. Piston coring was performed at 9 locations At Hoenam 1 out of 9 locations examined showed maximum depth, which was 90 cm and at Muneui 3 showed the minimum depth, which was 35 cm. At Hoenam, the release rate of TN was found to be $62.14~84.72;mg/ extrm{m}^2{cdot}day$ in 1998. However, it was found to considerably reduced to $23.20;mg/ extrm{m}^2{cdot}day$ in 2001. The release rate of TP was measured at $13.02~14.38;mg/ extrm{m}^2$.day at 1998, and it was reduced to $6.93mg/;mg/ extrm{m}^2{cdot}day$ in 2001.