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Cheryl Signs, P.E. <br />Western Sugar Pit <br />In accordance with approach no. 4, you have provided an affidavit dated November 1, <br />2010 that dedicates five of the Applicant's shares of GIC water and 4 shares of the Rural Ditch <br />water and portions of the water rights decreed in case no. 2001CW274 as replacement water <br />solely for this SWSP, Durham Pit SWSP (M78 -056), Kurtz Pit SWSP (M99 -006), and <br />Heintzelman Pit No. 116 SWSP (M09 -018) for as long as there are depletions at these gravel pit <br />sites or until such time as another replacement source is obtained. A copy of the affidavit is <br />attached to this letter. For the purposes of this SWSP, this affidavit will be accepted for the <br />dedication of the shares; however, if the State Engineer determines that a different affidavit or <br />dedication process is necessary to assure proper dedication of the shares, additional <br />information may be required prior to future SWSP approvals. <br />Depletions <br />The anticipated net depletions for this SWSP are 184.80 acre -feet per year. This SWSP <br />anticipates that a total of 62.81 acres of water surface will'be exposed at the site if dewatering ceases. <br />The evaporation calculations were based on the entire exposed surface area in the event that the <br />dewatering ceased and this SWSP will cover replacements for depletions associated with the 62.81 <br />acres. However for purposes of accounting, depletions will be based on the ground water surface area <br />actually exposed at the site. <br />Replacements <br />Page 2 <br />You have provided a monthly breakdown of the annual depletions made up of 158.44 acre - <br />feet of net evaporative Toss, 23.55 acre -feet of water lost with the mined product (which represents <br />800,000 tons of mined product), and 2.80 acre -feet of water used for dust control. <br />Computation of evaporation under this SWSP was also reduced during the ice covered period. <br />You have assumed the ice covered period to occur during the months of January and December, <br />based on the average temperatures of 26.0 °F for January and 27.4 °F for December; taken from the <br />Greeley weather station (053533). However, for the purpose of this SWSP, the Applicant shall <br />replace the net evaporation depletions from the exposed' ground water surface area that may occur <br />during the assumed ice covered period (the months of January and December) for any time that the <br />pit is not completely covered by ice. <br />Computation of the net evaporation during any time that the pond is not completely covered <br />by ice shall be determined as the pro -rata amount of themonthlygross evaporation rate distribution <br />amount identified in the State Engineer's General Guidelines for Substitute Supply Plans for Sand <br />and Gravel Pits, subtracting the pro -rata amount of the effective precipitation for that period. <br />The IDS AWAS stream depletion model was used to determine the lagged depletions from <br />dewatering, evaporation and operational losses to the Cache La Poudre River. The aquifer <br />characteristics used in the model are: transmissivity (T) = 100,000 gallons per day per foot, specific yield <br />(SY) = 0.28 (based on the USGS Water Supply Paper 1662D), the distance from the stream to the <br />centroid of the pit = 1,350 feet, and the location of the parallel impermeable boundary was estimated to <br />be 2,600 feet from the stream. <br />VCI proposes to provide replacement for this pit using water rights owned in the Last Chance <br />Ditch, Godding Ditch, Rural Ditch, Hayseed Ditch, lined gravel pits (112 Reservoir, Dakolios <br />Reservoirs and Von Ohlen Reservoir) and /or junior water decreed in case no. 2001 CW274. <br />7 <br />