Analysis of an Accuracy Degradation Factor of Discharge Estimation in a Multi-Dam System on the Syo River

Abstract

 Control of a multi-dam system requires accurate estimation of inflow and outflow. In Jinzu River, it is confirmed that river discharge is different from the outflow from a dam located above a hydrometric station. The author indicated that two problems of outflow caused the difference in discharge: accuracy of the P-Q curve and outflow calculation that ignored the effect of approach velocity head. In this paper the accuracy of estimation of inflow and outflow of dams on Syo River is discussed. In this study, the inflow of each dam reservoir was calculated using the inflow estimation method based on a digital filter. An outflow estimation error due to accuracy of the P-Q curve was confirmed by investigation of the inflow estimated by using a digital filter. And it was shown that a flood outflow from a dam gate can be improved by considering the approach velocity head. These problems of outflow confirmed at both of dams on Jinzu River and Syo River. Therefore, these results indicate that the outflow problem occurs at most of dams.