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<br />:387 <br /> <br />complex delivery locations and schedules are possible and the accounting, though more involved, <br />would be similar. <br /> <br />Operational Losses of Water <br /> <br />There are three types of losses in the operational analysis of the water bank. These losses are <br />applied to the consumptive use portion of the FLCC shares which has previously been determined. <br />The first is carriage losses inside the FLCC system. These losses in the internal delivery system can <br />be attributed to the main canal, the storage canal, and the lateral canals. Based upon system-wide <br />water balance studies as part of the Kansas vs. Colorado litigation, main canal losses average about <br />30, percent of the diverted water. Portions of this amount return to the river in the return flow <br />component, are pumped by wells or are consumed through evaporation and phreatophyte plants. <br />Lateral losses, estimated at 10 percent system-wide, suffer a similar fate. Similarly, the storage canal <br />losses are 17 percent of water diverted to storage. 'An estimated 11.56 percent of all deliveries of <br />water to storage along the 58-mile length is consumed in the storage canal and the remaining loss <br />portion is included in the return flow allowance. Data in Table 8.1 reflect the water balance <br />apportionment of these losses between consumed waters (permanently lost) and seepage waters, <br />stored in underlying aquifers or transported to the Arkansas River via groundwater movement as <br />return flows. Details of the apportionment are shown in Table A3.5 in the Appendix of the main <br />report. <br /> <br />River transit losses are the second type of loss. River losses are estimated using the USGS report <br />by Livingston (Livingston, 1978) which has been accepted by the winter water storage program and <br />the State Engineer. Transit loss under the Livingston method is calClllated as a volume per mile of <br />channel and is sensitive to four primary variables: antecedent flow rate in the river (cfs), the rate <br />of a planned reservoir release (cfs), duration of the release (days) and location along the river. The <br />method is applicable from Pueblo Reservoir to John Martin Dam in six subreaches, a channel <br />distance of 142 miles. By agreement, a form of the Livingston method is applied below John Martin <br />Reservoir. Within the scope of the research, losses can vary from 0.043 percent per mile at high <br />flows to 0.481 percent per mile at low flows of 5 cfs. Over 80 percent of the transit losses are due <br />to temporary storage of water in the banks. Only about 10 percent of water is permanently lost due <br />to phreatophyte consumption and evaporation. Overall, the river reaches have similar characteristics. <br />For the purposes of estimation, two reaches were used for this FLWB operational analysis; Pueblo <br />Reservoir to the FLCC headgate and FLCC headgate to John Martin Dam. As an example, for a <br />requirement of 220 aflmonth at the FLCC headgate (89.6 river miles below Pueblo Reservoir), a <br />reservoir release of 4.0 cfs or 246 af is needed if the existing base flow rate is 500 cfs. This is a loss <br />of 0.132 percent per mile. Actual losses are computed based on actual conditions. <br /> <br />The third type of loss is evaporation from storage. Standard practices were used in the analysis. For <br />Pueblo Reservoir, an annual percentage of 7 percent of contents of a storage account, varying on <br />a monthly basis, was considered similar to the assessments imposed by the USBR. For storage in <br />Adobe Creek Reservoir, evaporation loss is assessed as the FLCC estimates it, at 4.0 percent of <br />capacity per month over the summer diversion season of seven months (Smith, 1993). <br /> <br />8-17 <br /> <br />I <br />