Submitted to: Journal of Irrigation and Drainage Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/17/2005
Publication Date: 4/1/2006
Citation: Bautista, E., Clemmens, A.J., Strand, R.J. 2006. Salt river project canal automation pilot project: simulation tests. Journal of Irrigation and Drainage Engineering. 132(2):143-152
Interpretive Summary: Automated control of irrigation delivery systems potentially can help irrigation districts reduce operational spills, reduce operating costs, and improve the flexibility and accuracy of the water delivery service. Delivery service improvements in turn can help irrigators improve their on-farm irrigation practices. This paper describes a proposed automated canal control system and presents results of simulation tests conducted on a 30 km (19 mi) canal reach. The control system includes functions that can handle known demands and also unknown disturbances, including uncertain knowledge of canal properties. Tests demonstrated the effectiveness of the proposed control system when handling typical operating conditions. In such cases, the combined controller has to satisfy known demand changes while maintaining water levels close to their targets. The combined control system was less effective when dealing with atypical conditions, consisting of large unknown demand changes. However, even in such cases, the control system can potentially help improve performance relative to current manual operations. Such technology should be of interest to operators of large delivery systems such as the Bureau of Reclamation and irrigation districts, as well as to consultants.
Technical Abstract: The feasibility of automatically controlling water levels and deliveries on the Salt River Project (SRP) canal system through computer-based algorithms is being investigated. The proposed control system automates and enhances functions already performed by SRP operators, namely feedforward routing of scheduled demand changes, feedback control of downstream water levels, and flow control at check structures. Performance of the control system was tested with unsteady flow simulation. Test scenarios were defined by the operators for a 30 km, four-pool canal reach. The tests considered the effect of imperfect knowledge of check gate head-discharge relationships. The combined feedback-feedforward controller easily kept water level deviations close to the target when dealing with routine, scheduled flow changes. Those same routine changes, when unscheduled, were handled effectively by the feedback controller alone. The combined system had greater difficulty in dealing with large demand changes, especially if unscheduled. Because feedback flow changes are computed independently of feedforward changes, the feedback controller tends to counteract feedforward control actions. The effect is unimportant when dealing with routine flow changes but is more significant when dealing with large changes, especially in cases where the demand change cannot be fully anticipated.