THE ESTIMATION OF THE DIVERSION CHANNEL FLOW RATE BASED ON THE OBSERVED WATER LEVELS

Abstract

 This study examined the applicability of several flow discharge estimation methods using observed water levels to flow in a diversion channel. We used the following methods. (A) a ID estimation method using temporal changes of the water-surface profile. (B)a 2D and (C) a quasi-3D numerical model with the water level as boundary conditions. We conducted experiments of steady and unsteady flow in channels with diversion. In the experiments, we observed temporal changes in water level and discharge. The computed results were verified against the observed data to compare the accuracy of the methods. The comparison showed the following. (I) Analysis method (A) can reproduce the flow rates upstream and downstream of the diversion and the diversion with sufficient accuracy except for unsteady flow, (2) Analysis methods (B) and (C) can reproduce the flow rates when the diversion is not included, and (3) Analysis methods (B) and (C) can reproduce the flow rates when the diversion is included because strong 3-D flow is generated in case of weir backwater. ( 4) On the other hand, in the case of a lowered backwater, both analysis methods (B) and (C) can reproduce the main flow rate.