Stream-Bed Changes Downstream of Daecheong Dam in Korea

Stream-bed change is greatly influenced by the artificial factors such as Dam construction, gravel mining and river modification. The goal of this study is to compare the observed stream-bed change in Daecheong dam downstream in Korea with the estimated stream-bed elevation by GSTAR3 model. The difference between the observed and simulated values was examined. The river reach of downstream of Daecheong dam shows 2.29m degradation on average. However, the river reach of upstream of Daecheong dam appears 0.63m degradation on average for twenty four years. Though the estimated stream-bed changes using GSTARS3 model in the Daecheong dam downstream showed a degradation trend over all, it did not correspond with the observed one. An interception of sediment by Daecheong dam and a large scale gravel mining can induce a significant degradation of stream-bed. Consequently, it is expected that the large scale gravel mining caused on 76% of the total stream-bed degradation for the period.