Measure Q by means of a time-weight measurement. Now establish a hydraulic jump in the center of the length of the channel. This is done by using the downstream sluice gate. Continue to raise the downstream sluice gate gradually until the hydraulic jump becomes stationary and does not change position. Note that each time the upstream gate position is changed, the downstream gate position must be changed in the manner described above.
Flooding is avoided by quickly raising the upstream gate when the jump gets too close.
With a stationary hydraulic jump established in the center of the channel, measure the heights upstream and downstream of the jump at positions sufficiently far enough away from the jump to ensure an accurate measurement. The height measurements are made with the vernier depth gauges. Before using the gauge be sure to record the gauge reading when the gauge pointer contacts the bottom of the channel. The measured height is the difference between the gauge reading at a given depth and the gauge reading at the bottom of the channel. Once the depths have been recorded, raise the front sluice gate approximately three gear teeth.