Submitted to: United States Committee on Irrigation and Drainage Conference
Publication Type: Proceedings
Publication Acceptance Date: March 1, 2003
Publication Date: July 13, 2003
Citation: Clemmens, A.J. 2003. New calibration procedure for submerged radial gates. United States Committee On Irrigation And Drainage Conference. p. 399-408. Interpretive Summary: The total demand for water in the Western United States exceeds the available supply. Our ability to determine the amount of water diverted for various uses is crucial. There are many locations where measurement of water is either inaccurate or difficult and expensive. Radial gates are widely used in large water delivery systems. The traditional energy-equation calibration of submerged radial gates has been shown to be highly inaccurate in many situations. A new calibration method that uses both the energy and momentum equations has been proposed that overcomes the limitations of previous methods. The same equations are used for free flow, submerged flow, and with minor adjustment, the transition in between. These results should be of use to irrigation districts, consultants, municipalities, and federal agencies dealing with water issues, for example; the Bureau of Reclamation, Natural Resources Conservation Service, U.S. Geological Survey, etc.
Technical Abstract: Calibration equations for free-flowing radial gates typically provide sufficient accuracy for irrigation district operations. However, many districts have difficulty in determining accurate discharges when the downstream water level begins to submerge the gate. Based on laboratory studies, we have developed a new calibration method for free-flowing and submerged radial gates that allows for multiple gates and widely varying upstream and downstream channel conditions. The method uses the energy equation on the upstream side of the structure and the momentum equation on the downstream side. An iterative solution is required to solve these two equations, but this allows calibration from free flow to submerged flow right through the transition. Adjustments to the energy equation for free flow are described along with an additional energy adjustment for the transition to submerged flow. An application is used to describe the new procedure and how it overcomes the limitations of current energy-based methods.