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content was assumed to be 4% by weight, as suggested by the State Engineers Office. This <br /> results in an annual consumptive use of 5.9 acre-feet per year for water retained in the material <br /> hauled off the site (Table 2). <br /> No water will be diverted from the Wagner/Kauffman Pit#3 for dust control or washing of <br /> aggregate. <br /> The total calculated consumptive use during mining is estimated at 10.5 acre-feet for the year <br /> (Table 2). <br /> MINING STREAM DEPLETIONS <br /> Due to the fact that the site is set back from the river, the mining depletions were assumed not to <br /> be instantaneous. A stream depletion model was completed for the Wagner/Kauffman Pit#3 to <br /> display the lagged effect of the depletions (Appendix C). A summary of the monthly stream <br /> depletions due to the mining operation can be found in Table 3. <br /> The stream depletion model for the mining operation was developed under the following <br /> assumptions: <br /> • The estimated distance from the active stream was 200 feet. The location represents the <br /> down-gradient extent of the exposed surfaces as defined by the mining limits. <br /> • The transmissivity was assumed as 50,000 gal/H/day. There was no transmissivity data <br /> available for this area. A value of 50,000 gal/day/ft was chosen based on average <br /> transmissivity data for South Platte River tributaries similar to the Big Thompson River such <br /> as the St. Wain River and Boulder Creek. <br /> • The specific yield was assumed to be 0.2, which is typical for an alluvial aquifer. <br /> • The location of the parallel impermeable boundary was assumed to be a distance of <br /> approximately 3500 feet from the live stream. Source: USGS Geohydrology of the Shallow <br /> Aquifers in the Denver Metropolitan Area, Colorado. <br /> REPLACEMENT WATER <br /> Replacement water will be supplied from an existing lease with the City of Loveland for 11.0 <br /> acre-feet of fully consumable water. A copy of the lease is included as Appendix A. This lease <br /> expires on December 31, 2001. <br /> Kauffman and Son, Inc. used this 11.0 acre-foot lease to replace depletions at the Stroh Pit((M- <br /> 85-216), which lies adjacent to the Wagner/Kauffman Pit#3. The Stroh Pit has been lined and no <br /> Page 3 <br /> J <br />