Measurement often results in a decision to use less water.
This information can help make the best use of water supplies. By knowing the total amount of water flowing onto a measured border or field area, the irrigator can easily calculate the depth of water applied to the field. The best suited device depends on accuracy desired, ease of use, durability, availability, maintenance required, hydraulic characteristics, ease of construction, and installation cost. The devices measure the rate of flow in an open channel. Knowing the rate of flow and the time over which this rate is maintained, the total water volume used can be calculated.