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Non-Key Structures. The comma-separated output file lists Aggregate ID <br />and average permeability. <br />Based on soil permeability, determine soil classification by canal (see <br />relationship in Table B-3, Attachment B). <br />Based on the soil classification and canal length, select corresponding <br />efficiency as described in the approach section <br />Maximum Application Efficiencies <br />The StateCU model uses e maximum application efficiency to estimate the maximum <br />water available to meet crop consumptive use demands. StateCU calculates the actual <br />application efficiency by dividing the water delivered to the farm by the crop <br />consumptive use met with input river diversions. <br />Factors that affect maximum application efficiencies include: <br />• Irrigation practice (i.e., sprinkler versus flood irrigation) <br />• Crop types <br />• Soil types <br />Approach -Maximum Application Efficiencies <br />1. Review interviews with water administrators and ditch companies and extract the <br />following information from the resulting Key Structure Operating Memoranda as well <br />as from other available sources including summaries of water rights decrees, SPDSS <br />GIS irrigated acreage coverages, or published literature: <br />- Irrigation application method <br />- Application efficiency for each irrigation method <br />2. Review other published data for on-farm irrigation efficiencies in the South Platte <br />basin and adjacent areas. <br />3. Suggest appropriate maximum application efficiencies to use based on irrigation <br />methods. <br />Results -Maximum Application Efficiencies <br />As mentioned in the introduction, application efficiencies are dependent on irrigation <br />methods, which may vary with crop type and soils. In addition, irrigation methods and <br />planting practices have changed during the period considered in the SPDSS project. The <br />review of application efficiencies for the South Platte basin has largely consisted of a <br />review of efficiencies contained in water rights decrees. This review indicated <br />efficiencies range from 45 percent to 85 percent. Klamm and Brenner (1995) have <br />developed a list of recommended potential efficiency estimates by type of irrigation <br />system. A summary of the recommendations are shown in Table 1. Boesch (1995) also <br />reported a variety of application efficiencies that are dependent upon the irrigation system <br />type from a study done by the MRCS in Rocky Ford, Colorado. The findings of the study <br />encompass the values listed in Table 1. <br />Page 3 of 5 <br />