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Stephen Buechner, Applegate Group Page 2 <br />May 21, 2012 <br />and Canal Company to cover these potential long term depletions. Front Range <br />Aggregates must continue to commit those shares to this plan until such time as the <br />State Engineer authorizes the release of this commitment. <br />DEPLETIONS <br />Consumptive use of water at the property consists of 4.51 acre -feet (Table 1) of <br />evaporation from the 1.6 acres of exposed surface area within the settling ponds (0.5 acres), the <br />gravel washing-pond (0.1 acres) and the dewatering trenches (1.0- acre), 5.89 acre -feet of water <br />lost in product, and 10 acre -feet for on -site dust control (total 15.89 acre - feet -Table 2). The <br />Applicant anticipates that 400,000 tons of aggregate will be mined at the site during this SWSP <br />period. The material is mined above the water table and is not washed; therefore the water <br />retained in the mined product is considered to be 2.0% of the mined material by weight, which <br />equals 5.89 acre -feet. <br />Computation of evaporation under this SWSP was also reduced during the ice covered <br />period. You have assumed the ice covered period will occur during the months of December, <br />January, and February based on the Canon City weather station average temperatures of 22.5 °F <br />for December, 26.23 °F for January, and 24.13 °F for February. However, for the purpose of this <br />SWSP, the Applicant shall replace the net evaporation depletions from the exposed ground <br />water surface area that may occur during the assumed ice covered period (the months of <br />December, January, and February) for any time that the exposed ground water in the pit is not <br />completely covered by ice. <br />Computation of the net evaporation during any time that the pond is not completely <br />covered by ice shall be determined as the pro -rata amount of the monthly gross evaporation rate <br />distribution amount identified in the State Engineer's General Guidelines for Substitute Supply <br />Plans for Sand and Gravel Pits, subtracting the pro -rata amount of the effective precipitation for <br />that period. <br />You have provided a monthly breakdown of lagged depletions at this site in your attached <br />Appendix A. The IDS Alluvial Water Accounting System ( "AWAS ") stream depletion model was <br />used to determine the lagged depletions from dewatering, evaporation and operational losses to <br />Arkansas River. The aquifer characteristics used in the model are: transmissivity (T) = 55,000 <br />gallons per day per foot and specific yield (SY) = 0.2, the distance of the exposed ground water <br />to the stream = 1,250 feet, and the location of the parallel impermeable boundary was estimated <br />to be 2,400 feet from the stream. <br />During this plan approval period, no ground water will be used for reclamation, concrete <br />batching, or any other purpose. The total consumptive use and total lagged stream depletions <br />were calculated to be 20.43 acre -feet for the 2011 -2012 approval period. <br />REPLACEMENTS <br />The proposed sources of replacement water for this pit are an annual lease of 50 acre - <br />feet per year of fully consumable water from the Board of Water Works of Pueblo ( "PBWW "), <br />and the applicant's ownership of five shares of Twin Lakes Reservoir and Canal Company stock, <br />