Simulating daily runoff in hydrologic standard basin considering agricultural reservoir operation

The amounts of streamlow in the downstream are influenced from the operation of agricultural reservoirs upstream. To simulate daily streamflow by considering the operation of irrigation reservoirs upstream located in the standard basins, a system was constructed to simulate the amount of streamflow in order from upstream to downstream standard basins. The DAWAST model was selected to daily hydrologic runoff model, and daily reservoir water balance model was constructed. These two basic models were coupled to the system to simulate the downstream streamflow amount by considering the operation of reservoirs upstream. The Gemho river basin with watershed area of 2,092km² was selected to study basin, in which this basin was separated to 20 standard basins and has 21 reservoirs with total water storage above 1 Mm'. Using the system with runoff and reservoir water balance modules, daily streamflows at each junction were simulated and compared with each other in cases of considering and no considering upstream reservoir operations. And using the above daily simulated streamflows, flow duration curves were drawn and compared with each other. The streamflow amounts of standard basins considering reservoir operations were shown to less than those of no considering reservoir operations in case of agricultural reservoir with low storage capacity. But the Youngcheon dam with high water storage capacity of 81 Mm³ had a great influence on the downstream stream flow amount according to reservoir operation. The daily runoff modeling of considering upstream reservoir operation resulted more accurately than those of no considering reservoir operation.