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Michelle L. Hatcher <br />November 26, 2007 <br />Depletions <br />Page 2 <br />Ground water is exposed at the site. The ground water exposed at this site is estimated to be <br />24 acres with an annual depletion of 70 acre-feet. All ground water at the site was exposed after <br />December 31, 1980. <br />The remaining uses at the site are water lost in mined product, water used for concrete <br />batching and water used for dust suppression. The plan specifies that 58.9 acre-feet of water will be <br />removed in 2,000,000 tons of mined product, 2.0 acre-feet will be required for dust suppression and <br />15.5 acre-feet will be required for the production of 150,000 cubic yards of concrete. <br />If the pit is dewatered for dry mining, the plan estimates that the ponds will be dewatered at a <br />rate of 1,200 gpm for 8 hours a day, 365 days a year. The depletions resulting from dewatering <br />pumping will be replaced under this plan. <br />The depletions from evaporation, water removed in product, dust suppression and concrete <br />batching were lagged to the stream system using a Glover analysis and assuming a distance to the <br />no flow boundary of 7,603 feet, distance of the well to the river of 2,640 feet, transmissivity of <br />150,000 gpd/ft and specific yield of 0.2. <br />Replacements <br />The Applicant has an agreement with the City of Aurora ("Aurora") whereby Aurora will <br />continue to make releases of reusable effluent up to a maximum annual volume of 249 acre-feet <br />for the Lafarge SWSPs. According to the plan, 38.4 acre-feet of the 249 acre-feet available to <br />Lafarge will be used for replacement purposes under Lafarge's Combined South Platte SWSP. <br />Therefore, approximately 210.6 acre-feet remains of the total Aurora lease, which is more than <br />sufficient to augment the depletions for the Lupton Lakes mining operation. <br />The Aurora water will be released from Metro Wastewater Treatment plant, which is <br />located approximately 14 miles upstream of the mining site. A 0.5 percent per mile transit loss (7 <br />percent overall loss) has been accounted for in the replacement water available from Aurora. <br />If the site is dry mined, water discharged from the pit during dewatering operations that is <br />in excess of the lagged impacts of the dewatering operation itself will be used as a replacement <br />source. Prior to claiming credit for the water discharged to the river as part of the dewatering <br />process, the applicant must install adequate measuring devices with approval of the Division <br />Engineer to allow proper administration. <br />The monthly depletions and replacement requirements are found on the attached Table <br />C. <br />Conditions of Approval <br />approve the proposed substitute water supply plan in accordance with Section 37-90- <br />137(11), C.R.S., subject to the following conditions: <br />1. This plan shall be valid through October 31, 2008 unless otherwise revoked or modified. <br />If this plan will not be made absolute by a water court action by the plan's expiration date, <br />a renewal request must be submitted to this office with the statutory fee by September 1, <br />2008. <br />2. A well permit must be obtained for the gravel pit in accordance with §37-90-137(2) and <br />(11), C.R.S.. In addition, well permits must be obtained for wells 19490S, 7280R, <br />