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field that is easier to manage and this effect is reflected in the computer- ized irrigation analyses. Also, a common practice among most farmers is to irrigate in multiples of twelve hours per set. This practice was used 1n the computerized analysis. IRMA analyzed the effects of present irrigation practices to establish a base for recommending improvements and for measuring the effects of those improvements. It should be noted that results from evaluating present conditions are conservatively stated. The IRMA procedure contains no basis for considering effects of unleveled fields or of inaccuracy in water mea- surement. Therefore, present deep percolation losses may be somewhat higher than indicated because of imprecise measurement of water and" the lack of uniform water application on unleveled fields. Elements of the computerized analysis consist of two levels of struc- tural improvement, three levels of irrigation analysis, and two options for irrigation management. Levels of structural improvement include minimum and total improvements in existing ir~tion systems. Adding semi-automated improvementJrevel created a third level of structural controls to the total improvement. Three levels of improvement are shown 1n Table 11-2. Variables used 1n the computerized analysis of these levels for improving irrigation water management also are shown 1n Table 11-2 and consist of: (1) determining the time of set to the closest multiple of three hours as the time needed to apply the desired amount of water to the field during each irrigation using present flow rates and field layout; (2) determining the time of set to the closest multiple of twelve hours, determining the flow rate per furrow to the closest multiple of three gallons per minute and combining fields where desired by the landowner to determine the recommended time of set and flow rate needed for the desired application during each irrigation. "...~ II-7 ats ~. \'llO