2005-11-28_HYDROLOGY - M2000002 (3)

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Michelle L. Austin November 25, 2005 Depletions Paget The total annual losses resulting from evaporation, water bst in product, dust control and concrete hatching are shown in tits following table: TABLE B • LOSSES Site Name Evaporation Losses ao-ft Last in Product ao-ft Dust Contrd ao-ft Concrete Botching ao-ft Total (ao-ft) Howe Pit 0 19.87 4 12.8 38.67 Tanabe P'it 29.3 0 0 0 29.3 Dunes Develo ment 9.04 58.9 2 0 89.89 Mann Lakes 71.13 8.82 2.87 0 80.72 Ft Lu ton Ptt 11.8 0 0 0 11.8 Riverberxt O tlort 0 0 0 0 0 S Sto P 12.9 14.7 2 0 29.6 A slung wall wIN be Installed around the Stagecoach Stop Property so that the site vn"II be sealed from the 4ibutary grourxtwater. During the first two months of the mining operation the pit witi be dewatered and the water will be used to carsauct the slurry wall. Approximatey 81 acxe-feet of water will be pumped and used in the slurry wall construction in the first two months, or approximatey 30.5 acre-feet per month during October 2005 and November 2005. Ail process water for the Stagecoach Stop Property wilt be pumped from a new proposed well located inside the mining perntt boundary but outside of the slung wall. The water from the well witi be pumped into a small Ilned wash pond Inside the slurry wall lined ptt. You have assumed that the process water is 100% consumed. A mouthy breakdown of the lagged mining depletions are shown in the attached Table 1. Replaeements The proposes sources of replacement water are 25 shares of Fulton Ditch and tiny consumable water leased from the Cily of t3reeley, Consolidated Mutual Water Company and Saint Vrdin Left Hand Water Conservancy District. The Fulton Ditch water will be rocharged into Zigan Reservoir which Is a reclaimed gravel pit located in Section 35, Township 1 South, Range 87 West, 8°' P.M. The plan will also account for the impacts and credits from the devratering at the Stagecoach pit. The plan estimates that dewatering will occur for 8 hours per day, 385 days per year at a rate of 1,000 gpm. See attached Appendix C for the estimated credit and depletions from dewaterfng. The historic use of the 25 Fulton ditch shares yields 43.89 acre-feet of water during April through October while generating 5.25 acre-feet of return flow obligatlan during November through March. This quantifiption is based on the technique used fn the March 24, 1999 approval for the Fulton Lakes Pit, where the historic consumptive use values were determined using an anaysis decreed in qse number 82CW393. In this approach, headgate diversions were based on average mouthy values for the period of 1978-1988 and a 1096 conveyance loss was assumed as well as a farm efficiency of 50%. The return flow obligations, which were not addressed in the atwve decree, were calculated for this plan based on the assumption that all ,~-