|WAHLIN, BRIAN - WEST CONSULTANTS, AZ
Submitted to: Journal of Irrigation and Drainage Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/30/2004
Publication Date: 7/1/2005
Citation: Clemmens, A.J., Bautista, E., Wahlin, B.T., Strand, R.J. 2005 Simulation of automatic canal control systems. Journal of Irrigation and Drainage Engineering. 131(4):324-335
Interpretive Summary: Water supplies in the Western United States are not sufficient to meet current water demands, especially when considering water needed for environmental purposes. Agriculture=s share of available water is likely to decrease in the future. Agricultural water purveyors are being pressed by other water users to improve water control, while their water users are demanding more flexible water deliveries so they can more efficiently meet market demands. Operation of irrigation-water delivery systems can be improved by providing canal operators with better tools for determining control actions. Simulation modeling of water flow in irrigation canals, including operation of canal gates, provides a means of evaluating new operating methods, such as canal automation. While many unsteady-flow models for rive networks are available, their use in modeling irrigation canals, particularly automatic control of gates, is limited. In this paper, we examine three simulation models and their ability to adequately model the automatic control of irrigation canals. While all three models adequately model the operation of canals, there are a number of issues that limit their usefulness. These results should be of use to irrigation districts, consultants, the Bureau of Reclamation, and the developers of unsteady-flow river and canal simulation models. Ultimately better management of irrigation water supplies will conserve water and benefit the environment.
Technical Abstract: Simulation models for unsteady open channel flows have been commercially available for more than two decades. Most of these models are now available for personal computers and can be used to study the control of irrigation canals. Studies on automatic control methods and algorithms have been performed on at least half a dozen of the available unsteady-flow simulation models. Although, many of these automation studies have been conducted by the institution that created the simulation model, these simulation models were not created with automatic gate control in mind, and thus one has to be intimately familiar with the source code in order to implement sophisticated control features. Three commercially available unsteady-flow simulation software packages that allow automatic control of gates based on algorithms written by users are: CanalCAD from the University of Iowa, Hydraulics Lab; Mike11 version 3.2 from the Danish Hydraulic Institute; and Sobek from Delft Hydraulics. In this paper, we describe the various features of these unsteady flow simulation packages and how they interface to control engineering software/code. There are a number of tradeoffs between simplicity and functionality. All these models present difficulties and have limitations. The hope is to provide guidance on the next generation of unsteady-flow canal simulation models so that control functions can be routinely applied.