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• <br />• Forrest Leaf, P.E. <br />13946 CR 56 <br />Hillrose, CO 80733 <br />970) 39ti-8906 <br />970) 352-1982 FAX <br />ccwcdleaf®yahoo.com <br />LEAF ENGINEERING <br />June 21, 2001 <br />Kim R. Lawrence, Esq. <br />Lind, La«Tence & Ottenhoff <br />1011 - 11's Avenue <br />Greeley, CO 80631 <br />Re: Well injury analysis, S&H Mine <br />Dear Kim: <br />I have reviewed the proposed S&H gravel pit and the potential for injury to 16 imgation wells <br />and 9 domestic and stock wells. The 16 irrigation wells and 9 domestic wells aze located within <br />I.5 miles of S&H's proposed gravel mining operation. This letter report presents the potential <br />injury to the 16 irrigation wells and 9 domestic wells that would result from the dry-mining of 1 <br />acre gravel cells associated with S&H's gravel mine. <br />Figure 1 shows the location of the 16 imgation and 9 domestic wells. The irrigation wells are <br />used to provide irrigation water to cultivated crop land and have a long history of being used for <br />irrigation of said crop lands. The 9 domestic wells are used to provide domestic water to <br />numerous faint houses and also drinking water for livestock. <br />I calculated the historic aquifer response resulting from the pumping of the 16 imgation wells and <br />the 9 domestic wells simultaneously using the Theis method for unsteady radial flow in an <br />unconfined aquifer. In addition, I calculated the additional impact from the proposed S&H mine <br />using the same Theis method. <br />Aquifer properties were taken from the 1972 Hurr and Schneider open-file report "Hydrogeologic <br />Characteristics of the Valley-Fill Aquifer in the Greeley Reach of the South Platte River Valley, <br />Colorado". These properties included the aquifer saturated thickness and transmissivity. Decreed <br />pumping rates for the 16 irrigation wells were obtained from the State Engineer's tabulation. It <br />was assumed that the 9 domestic wells had a flow rate of 15 gallons per minute. <br />The injury analysis for the historic analysis was predicated on the assumption that each well was <br />pumping at it's decreed discharge rate simultaneously. The drawdown at each well was <br />LEAF ENGINEERING EXHIBIT <br />Hydrology ~ Hydraulics ~ Water Resources ~ Water Quality <br />Ei[.eaflAunikLLauTrntt S.4H well injury letter repon 2.wpd <br />