2011-03-21_HYDROLOGY - M1994027 - Laserfiche WebLink

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Jared Dains South Platte Combined Replacement Plan March 21, 2011 Page 7 Six of the shares of Whitney Ditch were historically used to irrigate 57.1 acres of pasture grass. Using a Blaney-Criddle analysis the potential crop consumptive use for the 57.1 acres was determined to be 96.8 acre-feet. Assuming a 15% ditch loss and 60% farm efficiency the dry year consumptive use was determined to be 84.64 acre-feet. The 2.5 shares of the Whitney Ditch were historically used for the irrigation of 24 acres. A total of 40 shares of the Whitney Ditch were recently changed in case no. 2002CW390 that was approved by the water court on September 26, 2007. As in case no. 2002CW390, this plan will estimate ditch loss to be 15 percent, a maximum farm irrigation efficiency of 60% will be used, and a return flow split of 50/50 between surface and subsurface return flows will be used. The total net consumptive use available for the dry-up of this 24-acre property is 37.3 acre-feet. For 2011, the applicant will utilize 12.5 shares out of the 13.5 Whitney Ditch shares. The expected consumptive use credit for the 12.5 Whitney Ditch shares has been estimated from a dry-up farm headgate delivery of 24.75 acre-feet per share (which include the 15% ditch loss) or approximately 309 acre- feet for the 12.5 Whitney Ditch shares. After accounting for the return flow obligations the total consumptive use credit for 2011 is projected to be approximately 195.74 acre-feet. This value is greater that the estimated dry-year yield because Aggregate owes lower than normal return flows in 2011 due to the small volume of deliveries made in 2010 (only approximately 177 acre-feet were delivered in 2010). The Whitney Ditch shares are measured and returned to the river at an existing structure located in the NW1/4 of Section 33, Township 6 North, Range 66 West. For accounting purposes the return flow requirement for the Whitney Ditch will be determined based on the calculated return flow factors. During the 2010 irrigation season Aggregate utilized the return structure owned by Hall- Irwin located in the SE1/4 of Section 30, Township 6 North, Range 66 West. Aggregate anticipates that this return structure will be utilized again in 2011. A copy of the agreement with Hall-Irwin needs to be submitted to the State Engineer's Office if the return structure will be utilized in 2011. Boyd & Freeman Ditch The 240 Boyd and Freeman Ditch shares were historically used to irrigate 85 acres of pasture grass. Using a Blaney-Criddle analysis the potential crop consumptive use for the 85 acres was determined to be 142 acre-feet. Assuming a 10% ditch loss and 55% farm efficiency the dry year consumptive use was determined to be 99.28 acre-feet. The applicant will utilize all 240 shares in this plan. The Boyd and Freeman Ditch shares are in the process of being sold to the City of Greeley. You indicated that the City of Greeley will allow Aggregate to use the Boyd and Freeman Ditch even after the sale is complete. However, before any credit can be taken for the Boyd & Freeman Ditch, accurate measuring and recording devices must be installed and those devices must be approved by George Varra, the District 3 Water Commissioner. The City of Greeley is currently designing an augmentation station for the Boyd and Freeman shares and anticipated that construction will be complete before the 2011 irrigation season. If the Boyd & Freeman augmentation station will not be installed, Aggregate will request more water from the City of Greeley and the Boyd and Freeman shares will not be used for replacement purposes during this plan period. The expected consumptive use credit for the 240 shares of the Boyd and Freeman has been estimated from a dry-up farm headgate delivery of 0.77 acre-feet per share (which include the 10% ditch loss) or approximately 184 acre-feet for all 240 shares. After accounting for the return flow obligations the total consumptive use credit for 2011 is projected to be approximately 142 acre-feet. This value is greater that the estimated dry-year yield because no deliveries were made in 2010,