Laserfiche WebLink
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 (CO DWR) database. A <br />36 -year period was available from 1974 to 2009, and that information was put into Table 2. <br />Table 3 shows the pro -rata monthly and annual diversions and then calculates the average <br />monthly and annual diversions for 27 of Western Fuels 115 shares. Table 4 shows the pro rata <br />portion of historical diversion records corresponding to the use of 34 of Western Fuels 115 <br />shares. <br />TRANSIT LOSSES IN THE CC DITCH <br />The CC Ditch travels approximately 16 miles from its diversion on the San Miguel to the point <br />of first delivery for irrigation and domestic uses. To correctly determine the amount of water per <br />share that is actually delivered to the point of use, it is appropriate to factor in a transit loss in the <br />canal. <br />The ditch rider has recently stated that, in reality, the ditch suffers transit losses of only 10% to <br />15 %. This is also consistent with the guideline used by the CO DWR of a transit loss of 1% per <br />mile of ditch. To be more accurate with the observable transit losses, this analysis uses 15% <br />average loss from the headgate to the fields. <br />CLIMATIC DATA FOR THE CONSUMPTIVE USE (CU) ANALYSIS <br />There are no weather stations that collect temperature and precipitation data in the Nucla area, <br />elevation 5700 feet. The closest stations are Norwood at elevation 7000 feet and Uravan at <br />elevation 5000 feet. In this case, the most logical and best method is to average the temperature <br />and precipitation data for the entire period of record for the two stations. These values are shown <br />in Table 5, and are used in the consumptive use calculations. <br />CONSUMPTIVE USE CREDIT DETERMINATIONS <br />Because of limited climate data available in the Norwood area, the Modified Blaney - Criddle <br />Method with the Pochop modification is the best method to determine crop CU. The Pochop <br />modification uses factors to adjust for high altitudes. Calculations in this method were done on a <br />monthly basis using only grass crop coefficients. There is some alfalfa in the area, but <br />observations revealed mostly pasture grass in the mining area. <br />Using the climate data described above, an elevation of 5700 feet, a latitude of 38 degrees <br />17 minutes, and starting and ending dates computed when the average temperature reached <br />45 degrees, the results showed a crop CU of 2.05 acre -feet per acre. These inputs and results are <br />shown in Table 6. <br />This analysis shows from the diversion records that the use of both 27 and 34 shares has not <br />produced a full water supply for the crop. Therefore, the CU must be calculated by determining <br />how much water arrives at the crop for each share and applying an irrigation efficiency. The <br />comparative values are shown in Table 7. <br />3 <br />