When placing a weir in an open channel, the measurement of the head should be taken upstream from the crest. The measurement location should be at least how far away from the weir?

Question

Quizplus · Accepted Answer

The measurement location of the head should be at least four times the head. Measurements of stream flow that are made with weirs are only accurate when the weirs are properly set and calibrated. It is important to read the head measurement at a point upstream of the weir crest that is not affected by the downward curve of the water as it approaches the weir.

When Placing a Weir in an Open Channel, the Measurement