Turbidity control in downstream of the reservoir: the Nakdong River in Korea

High turbid water in the river has been one of the major concerns to the downstream residence. During heavy local rainfall, high turbid water occurs in many countries located in the Asian monsoon climate region. The Andong and the Imha reservoir, two adjacent multipurpose dams, located in the upstream of the Nakdong River in Korea have suffered from severe turbid water problem. This study applied hydrodynamic water quality model CE-Qual-Riv1 to simulate turbidity propagation in downstream coupled with long-term watershed hydrologic model SWAT to consider contributions of tributaries. The outputs of runoff and suspended sediment in tributaries are incorporated into the input data necessary for the hydrodynamic water quality model. The simulation focused on the joint dam operation to minimize the negative impact of high turbid water in downstream river. Simulated turbidity in downstream shows a good agreement with the observed data, and the approach proposed in this study is applicable for establishing a sound turbid water management in downstream of the reservoir.