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Mr. Jared Dains May 17, 2011 <br />Middle Poudre Combined Plan - Lafarge West, Inc. Page 4 of 9 <br />A stream depletion model using the Glover method was used to calculate the lagged depletions <br />to the Cache La Poudre River. The alluvial aquifer model uses four aquifer input parameters for each <br />site as follows: 1) X-distance from well to river, 2) W-distance from the aquifer boundary through the well <br />to the river channel, 3) T-transmissivity of the alluvial aquifer (in gallons per foot/day) between the well <br />and the river, and 4) S-specific yield - 0.2 was used for all wells. The following parameters for each site <br />listed in the table below were used in the model: <br />Site Name T X W S <br />East Ri den Pit 55,000 250 5,800 0.2 <br />Three Bells Pit <br />Weitzel Pit 45,000. <br />50,000 500 <br />2-1900 4,800 <br />5,300 0.2 <br />0.2. <br />K er Pit 45,000 250 5,200 0.2 <br />Port of Ent Pit 55,000 250. 5,800 0.2 <br />Shields Mine 55,000 4,530 8,000 0.2 <br />According to the Applicant, the distance from the surface of the exposed ground water <br />area for each site to the Cache La Poudre River was measured based on the down gradient <br />extent of the exposed ground water surface (nearest point). For purposes of this SWSP, the <br />method used to measure the distance to estimate the lagged depletions will be accepted, <br />however any future SWSP must measure the distance from the exposed ground water surface <br />area for each site to the Cache La Poudre River based on the centroid of the exposed ground <br />water surface. <br />The total lagged mining depletions for all seven sites is 365.11 acre-feet. Real time depletions <br />were used for all six sites. <br />Replacements <br />Replacement water for this combined plan will come from the following sources: accretion credits <br />from recharge of 8.5 shares of the Box Elder Ditch, accretion credits from dewatering at the Three Bells Pit, <br />a lease from the City of Greeley ("Greeley") for fully consumable effluent, and a lease of augmentation <br />water provided by the Lake Canal Reservoir Company ("LCRC"). <br />Lafarge owns 8.5 shares in the Box Elder Ditch and will use all of the shares in this combined plan. <br />The shares will be diverted into a recharge pit (WDID 0302002) through an existing lateral from the ditch. <br />The recharge pit was constructed on the'un-mined portion of the Three Bells Pit site and it was excavated <br />to only the upper portion of the gravel deposit and will not expose additional ground water. The estimated <br />recharge pit size is one acre. For the purposes of this plan, evaporation from open water was assumed for <br />the entire surface area of the recharge pit for the number of days water was diverted into the recharge pit. <br />Based on this approach, the proportion of days with water diverted into the recharge pit to the number of <br />days per month was applied to the monthly gross evaporation rate, resulting in an evaporative consumptive <br />use from the recharge pit of approximately 2.04 acre-feet. <br />Lafarge owns 5.5 shares of the 6.0 shares of the Box Elder Ditch that were historically utilized for <br />the irrigation of the Three Bells property (344.3 acres). The dry-up acreage claimed for Lafarge's 5.5 <br />shares would be 305.6 acres of the 344.3 historically irrigated acres on the Three Bells property. The <br />historical consumptive use credit of the 5.5 Box Elder Ditch shares associated with the Three Bells <br />property was determined to be 281.4 acre-feet, based on a historical consumptive use analysis that was <br />completed in support of an application for an augmentation plan pending in case no. 2002CW205.