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Peter Wayland <br />November 18, 2014 <br />Page 3 <br />transmissivity (T) = 44,883 gallons per day per foot and specific yield, (SY) = 0.2, the distance from the <br />centroid of the exposed ground water to the stream = 860 feet, and the location of the parallel <br />impermeable boundary was estimated to be 3,500 feet from the stream. <br />Replacements <br />The proposed source of replacement for this pit is the historical consumptive use from 46.75 <br />acres historically irrigated with 0.5 shares of Hillsborough Ditch (WDID 04000523) diverted from the <br />Big Thompson River and previously used for irrigation on a portion of the mined property. Irrigation has <br />ceased on the Kirtright Pit site due to the mining operation and groundwater lakes. The Applicant owns <br />one share of the outstanding 118 shares of the Hillsborough Ditch. The one share of the Hillsborough <br />Ditch was historically used for irrigation on the Kirtright Pit mining site (93.5 acres). The historical <br />consumptive use was estimated using the Modified Blaney - Criddle methodology in the IDS <br />Consumptive Use Model, using the average monthly diversion from 1950 through 1986. The reach of <br />the Hillsborough Ditch is typically gaining between the river headgate and the Kirtright farm headgate. <br />Ditch loss is therefore not considered for the main ditch however 2 percent loss has been assigned to <br />the Kirtright lateral. Temperature and precipitation data was taken from the Fort Collins weather station. <br />Crops were irrigated through wild flood and furrows, therefore the irrigation efficiency was assumed to be <br />60 percent. Water in excess of the irrigation requirement was added to the soil moisture bank, which <br />was assumed to be three feet deep with a water holding capacity of 1.92 inches /feet. Irrigated crops <br />included silage corn and hay. Of the irrigation water historically applied to the farm, a portion ran off the <br />fields (surface return) and a portion seeped into the ground below the root zone of crops (deep <br />percolation). Return flows were assumed to consist of 50 percent of surface return flow and 50 percent <br />of deep percolation. The timing of surface return flows was assumed to be instantaneous to the stream <br />system. The timing of deep percolation return flows was estimated using the AWAS model alluvial <br />aquifer boundary condition option with the following aquifer parameters: transmissivity (T) = 44,883 <br />gallons per day per foot and specific yield, (SY) = 0.2, the distance from the centroid of the farm = 860 <br />feet, and the location of the parallel impermeable boundary was estimated to be 3,500 feet from the <br />stream. <br />The consumptive use analysis for the one share averaged 83.10 acre -feet per year. The <br />historical accretions /depletions for the 0.5 shares were prorated from the one share of the Hillsborough <br />Ditch that originally irrigated the property. The dry-year historical consumptive use credit from the 0.5 <br />share of the Hillsborough Ditch is 44.22 acre -feet with a non - irrigation season return flow obligation of <br />2.68 acre -feet (Table AI.3). After applying the 0.5 shares of Hillsborough Ditch water, there will be <br />20.78 acre -feet of uncompensated depletions. <br />Additional replacements for depletions during the non - irrigation season and during months with <br />insufficient credits will be made by releases will be made available throughout the year from a lease of <br />fully consumable water from the City of Loveland's Water and Power Department ( "Loveland "). A copy <br />of the lease associated with the mining operation was provided to the State Engineer's Office with the <br />SWSP request and is attached to this letter. The duration of the lease is for a term of twenty -five years <br />ending on December 31, 2022. The replacement water will be delivered to the stream at the Loveland's <br />wastewater treatment plant (WDID 0402300). The point of delivery is approximately 7 miles upstream <br />of the Kirtright Pit therefore a total transit loss of 14% (2% per mile) has been added to the replacement <br />water provided by Loveland. <br />Under the terms of the lease, replacements can be made using a variety of water owned by <br />Loveland including, but not limited to, Windy Gap reusable effluent, Loveland Storage Reservoir water <br />