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USE OF SHARES IN THE CC DITCH SYSTEM <br />Under the CC Ditch system, shares can be used on lands anywhere the owner calls for them; the <br />individual shares are not tied to a specific irrigated acreage. As a result, the shares have been <br />transferred to different properties, and there is a variation in the ratio of acres per share. <br />The 3,250 shares of the CC Ditch are used to irrigate approximately 5,288 acres. This <br />information was derived from the DWR database, based on a 2005 assessment of irrigated <br />acreage under the Ditch. <br />HISTORICAL DIVERSIONS OF THE CC DITCH <br />To determine the amount of water delivered for each share in the ditch, historical diversion <br />records were obtained from the Colorado Division of Water Resources (DWR) database. A <br />36 -year period was available from 1974 to 2009, as shown in Table 2. Table 3 shows the pro - <br />rata monthly and annual diversions, and the average monthly and annual diversions for 27 of <br />WFCs' 115 shares. Table 4 shows the pro rata portion of historical diversion records <br />corresponding to the use of the other 34 shares owned by WFC that are included in this report. <br />TRANSIT LOSSES IN THE CC DITCH <br />The CC Ditch extends approximately 16 miles from its diversion on the San Miguel River to the <br />first delivery point for irrigation and domestic uses. To correctly determine the amount of water <br />per share that is actually delivered to the point of use, it is appropriate to factor in a transit loss in <br />the canal. <br />The CC Ditch superintendent has recently stated that the ditch suffers transit losses of <br />approximately 10% to 15 %. This is also consistent with the guideline used by the DWR of a <br />transit loss of 1% per mile of ditch. To correspond with observable transit losses in the <br />CC Ditch, this analysis uses 15% average loss from the headgate to the fields. <br />CLIMATIC DATA FOR THE CONSUMPTIVE USE (CU) ANALYSIS <br />There are no on -site weather stations that collect temperature and precipitation data in the Nucla <br />area (elevation 5,700 feet). The closest stations are Norwood at elevation 7,000 feet and Uravan <br />(elevation 5,000 feet). In this case, the most logical method is to average the temperature and <br />precipitation data for the entire period of record for the two stations. These values are shown in <br />Table 5, and these rates have been used in the consumptive use calculations. <br />CONSUMPTIVE USE CREDIT DETERMINATIONS <br />Because of limited climate data available in the Nucla area, the Modified Blaney - Criddle Method <br />with the Pochop modification is the appropriate method to determine crop CU. The Pochop <br />modification uses factors to adjust for high altitudes. Calculations using this method were done <br />on a monthly basis using only grass crop coefficients, since observations revealed mostly pasture <br />grass in the mining area. <br />3 <br />