Flow Measurements in Open Channels Using Integrating-Floats

The flow measurements have increased importance in the last decades due to the shortage of water resources resulting from climate changes that request high control of the available water needed for different uses. The classical technique of open channel flow measurement by the integrating-float method was needed for measuring flow in different locations when there were no available modern devices for different reasons, such as the cost of devices. So, the use of classical techniques was taken place to solve the problem. The present study examines the integrating float method and defines the parameters affecting the acceleration of floating spheres in flowing water that was analyzed using experimental measurements. The method was investigated theoretically, as well as many experimental tests in a fixed floor laboratory flume were conducted. Different sizes of solid plastic spheres with different weights were used as floats to measure velocities and then discharge computation. The results indicate that the integrating-float technique is feasible and accurate for measuring low flow velocity in open channels. It was desirable to use small floats with specific gravity closer to unity to get more accurate results. The measured velocities and the estimated discharges were compared with discharges obtained using some other common laboratory measuring techniques. Good agreement was obtained between the integrating-float method results with the results of velocities obtained using other measurement techniques, with an error of less than 2.5%.