2014-04-22_HYDROLOGY - M1999050 - Laserfiche WebLink

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Mr. Todd Williams, P.E. April 21, 2014 Page 2 of 7 It is anticipated that 0.8 acre -feet of water will be used for on -site dust control during this plan period, based on an estimate of 5 truckloads of 4,000 gallons of water per month. Water used for dust control purposes is assumed to be 100% consumed. The Timnath- Connell Pit will not be mined for sand and gravel during this approval period, therefore there will be no water lost in mined product. The total annual consumptive use from evaporation (excluding the recharge pond) and operational uses at the site is 15.33 acre -feet (see attached Table 3). The Alluvial Water Accounting System (AWAS) stream depletion model developed by the Integrated Decision Support Group was used to determine the lagged depletions from the Timnath- Connell Pit to the Cache La Poudre River from past and projected evaporation and operational losses at the site. The following parameters were used in the model: • Distance from the centroid of the 6.03 acres to the river (X) = 2,218 ft • Alluvial aquifer width (W) = 5,300 ft • Specific yield (S) = 0.2 • Transmissivity (T) = 50,000 (gpd /ft) Lagged stream depletions are estimated to total 16.97 acre -feet during this plan period, as shown on the attached Table 4. The Applicant has continuously dewatered the Timnath- Connell Pit since 1999. Water pumped for dewatering is discharged into the adjacent recharge pond. This diversion into the pond is not a part of the metered Box Elder Ditch Shares that are also discharged into the recharge pond. The dewatering depletions are lagged to the river using the same parameters as the other lagged depletions from the Timnath- Connell Pit as described above. The dewatering accretions are lagged to the river using the same parameters as the site depletions with the exception of using a distance (X) from the centroid of the recharge pond to the river of 3,500 ft. This dewatering operation creates lagged accretions that mimic the lagged depletions. Thus at the cessation of dewatering the only depletion that would impact the river is that which is attributable to the "first fill" of the pit. The Applicant intends to line the pit when mining activity is complete thereby eliminating the depletion caused by the "first fill ". Should dewatering operations cease prior to the pit obtaining a liner approval from the Division Engineer, the Applicant must address the lagged depletions due to the "first fill." The SerFer Pit (M- 2008 -006, WDID 0303028) SWSP (WDID 0302534) is also operated by Connell Resources, Inc. and will rely on excess recharge accretions generated under the Timnath - Connelt SWSP and excess water leased from the City of Fort Collins as the source of replacement water. This use must be accounted for in the Timnath- Connell SWSP by showing the replacement supplies dedicated to replacement of depletions at the SerFer Pit as a debit against this plan. For this approval period, the total debit to the Timnath - Conned Pit due to the dedication of replacement supplies to the SerFer Pit is 8.41 acre -feet. Replacements Connell Resources, Inc. owns a total of 4.0 Box Elder Ditch Company ( "BEDC ") (WDID 0300926) shares that were part of 64 shares historically used to irrigate the property known as the John Weitzel Farm, which is the site of the Timnath Connell Pit. The primary source of replacement water for this SWSP will be from recharge of 2.5 of these BEDC shares. The shares will be diverted into a recharge pit (WDID 0302059) located on the Timnath- Connell site. The recharge pit was constructed in an area of the mining site that was previously excavated for sand and gravel mining. The remaining 1.5 BEDC shares not used for recharge will continue to be used to irrigate the portion of the John Weitzel Farm still in agricultural production.