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Title: INFLUENCE OF CANAL GEOMETRY AND DYNAMICS ON CONTROLLABILITY

Author
item STRELKOFF, THEODOR - UNIVERSITY OF AZ, TUCSON
item DELTOUR, JEAN-LUC - GERSAR, FRANCE
item BURT, CHARLES - CAL POLY, SLO, CA
item Clemmens, Albert
item BAUME, JEAN

Submitted to: Journal of Irrigation and Drainage Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/27/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Much of the water supplied to irrigated farms is delivered through networks of canals. Competition for water and the desire to reduce negative environmental effects from irrigated agriculture are prompting the need for better control of canal operations, which in turn is expected to improve the potential efficiency of farm irrigation systems by providing water more consistent with crop and field irrigation system needs. However, open canals are not always easy to control, depending upon their hydraulic properties. This paper presents some of these canal hydraulic properties and shows that influence of these properties on water delivery operations can be systematically examined. Important canal hydraulic characteristics include how the volume in the canal changes as the flow rates and water levels change, how waves (sudden upstream flow changes) propagate through the canal, and how the canal water levels respond to sudden changes in demand. These results are useful for irrigation district engineers, consulting engineers, and others who are interested in determining what types of hydraulic structures and operating procedures to use on a particular canal or in the design of new canals and their associated structures.

Technical Abstract: This paper presents the results of the Task Committee on Canal Automation Algorithms with regard to the influence of canal properties on the controllability of irrigation canals. While the control provided by individual algorithms was not evaluated, studies were performed to illustrate inherent hydraulic limitations--the inability of canal pools to recover rapidly from disturbances or flow perturbations. Studies were performed in nondimensional form to develop a better understanding of how pool properties influence pool response. Three such studies were performed. First, nondimensional backwater curves were developed for a range of canal conditions. The second study involved the propagation of waves initiated at the upstream end of a canal pool, as this is influenced by downstream boundary conditions. Finally, the response of pools to downstream withdrawals was examined in terms of their sluggish recovery even when the correct flow change is applied upstream. These results will help in understanding how canal properties influence the ability of operators to control effectively a canal either manually or automatically and should influence future design practices.