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A <br /> <br />the ragged effect of the depletions (Appendix A). Asummary of the monthly stream depletions <br />due to the mining operation can be found in Table No. 4. <br />The stream depletion model for the mining operation was developed under the following <br />assumptions: <br />• The pumping well was placed 250 feet from an active stream. The location represents the <br />down-gradient extent of the exposed surfaces as defined by the mining limits. <br />• The transmissivity was assumed as 55,000 gal/day/ft. This value was assumed to be the <br />-same as the transmissivity of a pump test well in the area. Source: Groundwater Circular <br />No. 11, Loc. B7-68-22aba2 (Appendix A). <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 5800 <br />. feet from a live stream. Source: USGS Depth to the Water Table in the Boulder-Fort <br />Collins-Greeley Area; Front Range Urban Comdor, Colorado. <br />BOX ELDER DITCH SHARES <br />Flatiron Co. owns the 8.0 Box Elder shares, which historically irrigated the East Rigden <br />property. The Flatiron Co. has the long-term augmentation responsibility for this site and will <br />provide the necessary amount of Box Elder shares for summer replacements and recharge credit. <br />The 8.O Box Elder Ditch shares that historically irrigated the East Rigden property were <br />committed fo the original substitute supply plan for the site in a 1490 Report completed by W.W. <br />"Wheeler and Associates, Inc. The Wheeler report completed the original consumptive use <br />..analysis for these shares. There are a total of 64 shares in the Box Elder Ditch. <br />The 8.0 shares that were committed to the original Wheeler plan made replacements for three <br />different mining sites. Lafarge submitted a letter to the SEO dated July 15, 1993, which stated <br />that 2.6 of the Box' Elder Ditch shares were specifically for replacements at the East Rigden Pit. <br />It is proposed that a total of 3.0 shares be used as direct replacement in this renewal. <br />This renewal -uses updated diversion records for the Box Elder Ditch for the period 1950 to 1997 <br />to estimate the consumptive use. They are included in column "A" in Table No. 3. <br />Using a 10% ditch loss and 55% farm efficiency, the water available for crop consumption was <br />determined for the 8.0 shares in column "D" in Table No. 3. The new consumptive use credit <br />was determined by choosing whichever value was less, the water available for crop consumption <br />or the-net crop consumptive use from the 1990 Report. This results in a new consumptive use <br />credit of 327..3 acre-feet for the 8.0 shares, which is listed in column "F" in Table No. 3. <br />Page 3 <br />