Wayne Clyma

Optimal Design of Furrow Irrigation Systems

ABSTRACT GENERALIZED geometric programming and the Soil Conservation Service design procedure were combined to optimize furrow irrigation systems design based on minimum costs. Water, labor, and ditch con-struction were the costs considered. The system decision variables were the inflow rate, time of inflow, length of run, number of lengths of run, number of sets, and number of furrows per set. An example field was design-ed considering the cost coefficients, design variables and system constraints. Recommendations for further im-proving the design procedure by basing the design on maximum profit and including additional decision variables were given.

The Management Improvement Program (MIP): A Process For Improving the Performance of Irrigated Agriculture

Enhanced long-term management ofnatural resources, farmer profitability, and overallsocial well-being are essential to sustainableirrigated agriculture. Because these objectives oftenseem to conflict, all agriculturalstakeholders – farmers, irrigation districts, supportand regulatory government agencies, and otherinterested parties – need to interact proactively toidentify and address common needs. To this end, theManagement Improvement Program (MIP) was tested in theMaricopa-Stanfield Irrigation and Drainage District(MSIDD) area in central Arizona, USA, as a managedchange process to improve the performance of anirrigated agricultural system. The three-phased MIPprocess consists of (1) analysis of the currentperformance of the agricultural system, on- andoff-farm, to gain a common, shared understanding; (2) developmentby the stakeholders of plans foralternatives to address identified opportunities forimprovement; and (3) collaborative implementation ofthe plans. This paper describes the MIP process andits methodological origins, provides an account of theinitial application of the MIP process to an irrigatedagricultural system in the United States, andhighlights some important outcomes of the MIPapplication.

Analysis of basin irrigation performance with variable inflow rate

Abstract Basin irrigation systems were designed for a constant flow rate. The operation of the designed system was simulated using the zero-inertia model of surface irrigation. The performance of the system was obtained for modified design flow rates. Three patterns of flow variation — sinusoidal, initially low then high, and initially high then low — were studied. The average of a variable flow rate in a given simulation equalled, was less than and greater than the design flow rates. The flow rate variations did not lower the performance of the system when the average flow rate during irrigation was greater than or equal to the design flow rate. Significant reductions in system performance occurred when the average flow rate was equal to 50% of the design. Basin irrigation systems should be designed for the average of the variable flow rate available at the field outlet.

Level Basin Design and Management in the Absence of Water Control Part I: Evaluation of Completion-of-Advance Irrigation

ABSTRACT Zero inertia modeling was used to evaluate completion-of-advance irrigation in level basins with no run-off for use where inadequate control of water delivery exists. Distribution uniformity was good to extremely high for a wide range of conditions. The average depth of infiltration varied only moderately with large differences in the unit inflow rate. The effects on performance caused by errors in the soil surface parameters were moderate and can be compensated for. Completion-of-advance irrigation can be used by farmers to manage the application of a specific amount of water in the absence of water control.

Level Basin Design and Management in the Absence of Water Control Part II: Design Method for Completion-of-Advance Irrigation

ABSTRACT Level basins are designed based upon completion-of-advance irrigation. Designs are used for fields where water control is not practical or practiced. The design determines either the run length or the infiltrated depth when the other is specified. The resulting design provides for applying a relatively constant infiltrated depth when the unit inflow rate varies by a factor of four from a target unit inflow rate.

Optimizing Surface Irrigation System Design Parameters: Simplified Analysis

ABSTRACT THE geometric programming method was described. Simple techniques such as monotonicity analysis, constraint activity, and condensation were utilized to reduce the size of the problem. Example optimal designs for borders and furrows were solved on a hand calculator following the suggested methodology. Results were the same as previously obtained from generalized geometric programming and extensive use of a digital computer. Globally optimal solutions for minimum cost and max-imum profit designs were obtained by using this mathematically rigorous but simple optimization pro-cedure.

On-farm system performance in the Maricopa-Stanfield Irrigation and Drainage District area.

A detailed Diagnostic Analysis (DA)was performed on an irrigation district in CentralArizona as part of a Management Improvement Program(MIP). The DA was conducted by an interdisciplinaryteam who focused their findings on performance of theirrigated agricultural system, on- and off-farm,rather than on disciplines. This paper reports on thefindings related to on-farm management. Specificfindings are presented relative to farm water use,soil sustainability, the interactions between the farmirrigation system and the water delivery system, andthe adoption and transfer of new technology. Theresults point to the need for appropriate applicationof technology, ongoing farmer education, andcoordination of farm and district operations andgovernment agency programs. The interdisciplinarynature of the DA team was essential for properlyassessing performance. Although this study was donein the state of Arizona in the USA, the methodologyused and some of the general conclusions areapplicable to other locations, both within and outsidethe United States.

Diagnostic Analysis of the Maricopa-Stanfield Irrigation and Drainage District Area

Diagnostic Analysis (DA) is a methodologyfor assessing and understanding the performance of anagricultural system. This analysis is thefirst step in a large system change process, known asthe Management Improvement Program (MIP), whoseobjective is to improve the performance of the agricultural system.A group of Federal andstate of Arizona agencies agreed to apply the MIPmethodology in a western U.S. setting. The purpose of theapplication was to test the applicability of the MIPapproach and to refine themethodology. This paper describes how the DAmethodology was applied in the Maricopa-StanfieldIrrigation and Drainage District (MSIDD) area incentral Arizona, USA, and summarizes the lessonsderived from that experience. Specific findings ofthe DA study and the response of MSIDD areaagriculture to those findings are discussed inseparate articles.

Water delivery performance in the Maricopa-Stanfield Irrigation and Drainage District

A Diagnostic Analysis was conducted in the service area of theMaricopa-Stanfield Irrigation and Drainage District in Arizona,USA. The study was an initial step in a managed change process,named Management Improvement Program (MIP), aimed at improvingthe performance of the areas irrigated agricultural system. Partof the Diagnostic Analysis study focused on the performance ofthe irrigation districts water delivery service. The studyidentified areas of high and low water delivery performance,factors contributing to the observed levels of performance, andimplications to on-farm water management. These findings promptedchanges in the delivery systems management. Results from a post-MIP intervention study indicate that the districts waterdelivery performance has improved as a result of those changes,and thus, that the Diagnostic Analysis and MIP methodologies areeffective tools for promoting positive change in a water deliveryorganization.

Delivery system performance case study: Wellton-Mohawk irrigation and drainage district, USA

An irrigation district in southwestern Arizona was studied to assess the performance of its water delivery system. Data were obtained through monitoring of lateral canals, examining water order reports and bills, and conducting a diagnostic analysis of the water delivery and on-farm irrigation systems through interviews. A number of differences between official andde facto district operating policies were found. These policies had changed over the years and provided far more flexibility and better service than provided by the original official policy. The canal system, which was designed to be operated under upstream control, was found to be operated under a complex mixture of manual upstream and downstream control that resembled dynamic regulation. Farmers made official (recorded) water orders only about half the time. Deliveries usually occurred within one day of the ordered date, as per district policy, with more late deliveries at the tail end of the system during peak water use periods. On average, the district delivered the rate and duration ordered, but average flow rates for individual deliveries were not accurately estimated due to fluctuating flows. The two biggest shortfalls observed were the lack of water measurement records at intermediate points in the system and lack of thorough water accounting. These shortfalls appeared to have had only a minor effect on overall district objectives.