Submitted to: Environmental and Water Resources Institute World Congress Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/1/2008
Publication Date: 5/15/2008
Citation: Zerihun, D., Bautista, E., Strelkoff, T., Sanchez, C., Clemmens, A.J., Niblack, M. 2008. Evaluation of basin inflow cutoff criterion in the irrigation districts of southwest arizona. Environmental and Water Resources Institute World Congress Proceedings. CDROM. 10 pp.
Interpretive Summary: Guidelines for determining an appropriate cutoff time can help improve the performance of surface irrigation systems. Difficulty in developing practical guidelines is the uncertainty of system properties and inputs. A research project, involving the USDA-ARS-ALARC, University of Arizona, and the USBR, is developing cutoff criteria for border systems in the Yuma area, where performance of many surface irrigation systems is poor and flow measurement and control is inadequate. A proposed strategy uses the time of advance to half the field length as a criterion for estimating the actual inflow to the field and, consequently, the recommended cutoff time. This article presents the results of initial simulation and field studies that examine the feasibility of such a management strategy. Results of this study should be of interest to other researchers interested in developing management tools for surface irrigation systems. If successful, the USBR hopes to promote the resulting guidelines among irrigators in the Yuma area.
Technical Abstract: Low irrigation efficiencies persist in irrigated areas near Yuma, Arizona due to poorly designed irrigation systems, poor condition of existing systems, inaccurate delivery of flow rates, and inadequate criteria for determining irrigation cutoff. In farms where growers lack adequate control over the water supplied to individual basins, conventional irrigation cutoff criteria, based on precise measurement of inflow rates, are ineffective. A research project, involving the USDA-ARS-ALARC, University of Arizona, and the USBR, is exploring the management of these systems using the time of advance to half the field length as a criterion for cutoff when inflow rates are not know accurately. Preliminary simulation studies have shown the potential benefits and limitations of such a strategy. This strategy is being tested in the field, to assess its sensitivity to uncertain system properties. This article describes the general research methodology and some of the initial simulation and field results.