ACCURACY DETERIORATION OF INFLOW AND OUTFLOW ESTIMATION AT SMALL DAM RESERVOIR DURING FLOOD PERIOD

Abstract

An inflow into the dam reservoir is estimated from a time variation of the hydrostatic water level. Therefore, a noise of the water level time series data originated from a water surface oscillation cause an oscillation of estimated inflow. In Jinzu river, it is confirmed that river discharge is different from outflow from a dam above the river discharge observation station at flood time. But, this problem was not able to explain by the noise in time series of water level.
The accurate outflow from dam is able to estimate by considering the effect of velocity head. The outflow corrected by velocity head is evaluated by analysis using unsteady flow model. These results is able to indicate that the difference between river discharge and outflow of dam is derived from estimation error of outflow.