The increase of summer rainfall intensity caused by recent climate change brings a multiplicity of serious problem in water resources management. The turbidity caused by soil erosion has become a very important environmental issue in water resources management and utilization.
Our country depends on dams for about 40% of current water supply and that demand is continuously increasing because of economic growth and a rise in the standard of living. The dependence on dams increases and more in spite of the demand management and the diversification of water sources. In this situation, a measure of preparation of turbidity management in major multipurpose dams is extremely urgent. Thus, this study is an analysis of the correlation of outflow discharge and turbidity decrement to provide the foundation of the rational turbidity exclusion operation plan which considers the characteristics of dams.
Results from the application of CE-QUAL-W2 to Imha reservoir were based on data is measured from automatic measuring equipment of Imha reservoir from July 10-17, 2006, and show tendency and water depth in which occur the highest turbidity, but in the case of density it was evaluated lowly, in the case of density of highest turbidity it was evaluated highly, the comparison result was classified by water depth in dam body and was evaluated lowly, and the simulation results of high density turbidity and the layer of high density turbidity by the result of error analysis which include measure data and simulation data are in agreement.
The simulation results from variation of turbidity in Imha reservoir by creating seven scenarios which are classified by discharge size and discharge location. In case of turbidity decrement, the selective exclusion is more effective than the surface exclusion, and the time when it becomes the fixation level of turbidity discharge is when the discharge quantity will be large it was short, but that time the remaining turbidity quantity of reservoir showed the tendency which is inversely proportional.
Estimated results show turbidity exclusion quantity of about 1㎥ discharge quantity will be small turbidity exclusion quantity about 1㎥ and discharge quantity will be high in both cases of total turbidity quantity in reservoir and turbidity discharge of 30 NTU, but in case of 50 NTU, 100 NTU doesn't find any special interrelation. It seems that this is the result of inappropriate application about turbidity discharge location classified by scenarios during model application. And hereafter, model tests will lead and it is a portion that must be verified.