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Property was continuously irrigated with the 6.0 Box Elder shares from 1950 to 1984. The <br />historic crop rotation was divided between five crops over the study period. These included <br />approximately 97.9 acres of corn, 26.2-acres of alfalfa, 207 acres of pasture gra§s, 6.6 acres of <br />bazley, and 6.6 acres of bearis. The property was-flood irrigated and the season was <br />approximately April 15 to September 30. - <br />The"South Platte Consumptive Use Model (SP CU) was used to calculate the irrigation demand . <br />from this crop rotation pattern during the study period. This model includes.a Modified Blaney- <br />Criddle analysis for each crop grown during the study period to determine the potential crop <br />consumptive use. The.carryover soil moisture is also included in, the calculation of imgation <br />demand in the"5P CU model. The previously mentioned crop rotation for the farm was used in ° <br />the SP CU model for the 344.3 acres. The temperature, precipitation, and frost dates from the <br />City of Fort Collins Weather Station were used in the analysis. The water.demand analysis <br />resulted in a total annual irrigation requirement of 404.0 acre-feet for this crop rotation during the <br />study period (Table No. 2). <br />Again, the Box Elder Ditch diversions from 1950 to 1984 were used to detennine the water <br />supply (Table No. 2). Using a 10% ditch loss and 60% farm efficiency, the water available for <br />crop consumption was determined for the 6.0 shares in column "D" in Table No. 2. The <br />consumptive use credit was deternned by choosing whichever value was less, the water " <br />available for crop consumpfion or the net crop consumptive use. This results in a new <br />consumptive use credit of 307.0 acre-feet for the 6:0 shares; which is listed in column "F" in <br />Table No. 2. <br />Return flows were assumed to be 33%surface and 67% subsurface. A stream depletion model <br />was used to determine the timing of the lagged subsurface return flows. The return flows . <br />accruing to the Poudre River were modeled under the following assumptions: <br />• The centroid of the Three Bells Property irrigated with the 6.0 Box Elder shazes is " <br />approximately1500 feet from-fhe Poudre River. <br />• The transmissidity was assumed as 50,000 gal/day/ft. This value was assumed to be the <br />same as the transmissivity of a pump test well in the azea. Source: Groundwater Circular <br />No: 11, Loc. B6-68-Ibaa (Appendix A). <br />• The specific yield.was assumed to be 0:2, which is typical for an"alluvial aquifer. <br />• :The location of the parallel impermeable boundary" was assumed to be a distance of 4800 <br />feet from a live stream. Source: USGS Depth to the Water Table in the Boulder-Fort " <br />Collins-Greeley Area, Front Range Urban Corridor, Colorado. <br />The return flow analysis is included in Appendix A for your review. The historic irrigation credit and - <br />return flow obligations are presented in Table No. 2. The historic accretions and depletions for the <br />6.0 shares were prorated to determine the values for 5.0' shazes used in this plan. The historic <br />consumptive use credit from the 5.0 Box Elder Ditch shares used in this augmentation plan from the <br />Tliree Bells Property is 255.9 acre-feet (Column "L" Table No. 2). <br />Page 2 <br />