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U Ms. Jennifer Lindahl, P.E. Page 2 of 4 June 5, 2015 therefore Pit No. 20 was not included in the current substitute water supply plan. An amended SWSP will be sought if mining at Pit No. 20 will occur during the plan period and replacements are still unable to be made pursuant to case no. 2000CW142. Pit No. 21 Pit No. 21 is proposed to be lined upon completion of mining and therefore will not require permanent augmentation. LRM therefore proposes to operate Pit No. 21 pursuant to a substitute water supply plan until mining at Pit No. 21 is completed and the pit is lined. LRM will submit a substitute water supply plan request for Pit No. 21 at least six months in advance of commencement of mining at Pit No. 21. Anticipated Depletions Pit No. 21 is proposed to be continuously dewatered during mining operations, at an anticipated initial dewatering rate of 300 gallons per minute. The pumping rate is expected to decrease as dewatering progresses. The water will be pumped into LRM's unlined Pit No. 20 where it will infiltrate into the ground and be recharged back to the stream. Any evaporative depletions resulting from the water delivered to Pit No. 20 will be covered under the plan for augmentation decreed in case no. 2000CW142. The monthly depletions from dewatering at Pit No. 21 and the resulting accretions from delivery of the water to Pit No. 20 will be lagged to the Big Thompson River using the Alluvial Water Accounting System (AWAS), which uses the Glover method. The following parameters are used in the model: the distance (X) from the centroid of the exposed ground water surface to the river, the width (W) of the aquifer on the side of the river where the pit is located, the harmonic transmissivity (T); and the storage coefficient (S). The parameters used for each pit are shown in the table below. Glover ParamPtPrs Pit Name X (ft) W (ft) T (gal/day/ft) S Pit No. 21 (depletion) 1,499 2,070 35,014 0.2 Pit No. 20 (recharge) 1,071 2,105 34,264 0.2 The anticipated lagged dewatering depletions and accretions are shown in the attached Table 1. Since Pit No. 20 will be located slightly closer to the stream than Pit No. 21, lagged recharge from dewatering is projected to slightly exceed lagged depletions from dewatering for the first ten months. As long as the pit is continuously dewatered, the water returned to the stream system should be adequate to offset the depletions attributable to the dewatering operation. Once Pit No. 21 is lined and is no longer being dewatered, depletions from dewatering are projected to lag out approximately ten months and total 14.9 acre-feet. LRM will replace the lagged depletions after cessation of dewatering with their available replacement supplies. Consumptive use at Pit No. 21 will consist of water removed with the mined product, concrete production, and dust control. You have stated that total production numbers at the