EFFECT OF PLAN AND CROSS SECTIONAL SHAPES ON ACCURACY OF DISCHARGE MEASUREMENT BY MEANS OF FLOATS

Abstract

Discharge measurement is one of the most important subjects for river planning. The measurement through floating device, which is a typical method as the Lagrangian method, is being adopted extensively. Most of the rivers in Japan are compound meandering channels, which have complex flow field. Many of these rivers have phase difference between main channel and levee, and the flow fields due to phase differences become more complex. Therefore, we have to check the accuracy of the discharge measurements of those compound channels.
In this paper, we have presented the method of three-dimensional analysis of compound meandering channel. And we have checked the accuracy of discharge measurements. It is observed that the measurement values of those channels with phase difference have large errors. Those errors might be reduced by increasing the number of floating devices in the flood channel.