Laserfiche WebLink
Mr. Todd Williams, P.E. Page 2 of 6 <br />March 24, 20115 <br />positive accretion or depletion from the pond and is thus not included in the total net depletions <br />covered in this SWSP. <br />It is anticipated that 0.8 acre -feet of water will be used for on -site dust control during this <br />plan period, based on an estimate of 5 truckloads of 4,000 gallons of water per month. Water used <br />for dust conirol purposes is assumed to be 100% consumed. <br />The Timnath- Connell Pit will not be mined for sand and gravel during this approval period, <br />therefore there will be no water lost in mined product. <br />The total annual- consumptive use from evaporation (excluding the recharge pond) and <br />operational uses at the site is 15.33 acre -feet (see attached Table 4). The Alluvial Water Accounting <br />System (AW�S) stream depletion model developed by the Integrated Decision Support Group was <br />used to determine the lagged depletions from the Timnath- Connell Pit to the Cache La Poudre River <br />from past and projected evaporation and operational losses at the site. The following parameters <br />were used in the model: <br />• Distance from the centroid of the 6.03 acres to the river (X) = 2,218 ft <br />• Alluvial aquifer width,(W) = 5,300 ft <br />• Specific yield (S) = 0.2 <br />• Transmissivity (T) = 50,000 (gpd /ft) <br />Lagged stream depletions are estimated to total 15.75 acre -feet during this plan period, as shown on <br />the attached Table 4. <br />1 <br />The Applicant has continuously dewatered the Timnath- Connell Pit since 1999. Water <br />pumped for�dewatering is discharged into the adjacent recharge pond. This diversion into the pond <br />is not a part of the metered Box Elder Ditch Shares that are also discharged into the recharge pond. <br />The dewatenng depletions are lagged to the river using the same parameters as the other lagged <br />depletions from the Timnath- Connell Pit as described above. The dewatenng accretions are lagged <br />to the river !using the same parameters as the site depletions with the exception of using a distance <br />()) from the centroid of the recharge pond to the river of 3,500 ft. This dewatenng operation <br />creates lagged accretions that mimic the lagged depletions. Thus at the cessation of dewatenng the <br />only depletion that would impact the river is that which is attributable to the "first fill" of the pit. <br />The Applicant intends to line the pit when mining activity is complete thereby eliminating the <br />depletion caused by the "first fill ". Should dewatenng operations cease prior to the pit obtaining a <br />Liner approval from the Division Engineer, the Applicant must address the lagged depletions due to <br />the "first fill." <br />Replacements <br />Connell Resources, Inc. owns a total of 4.0 Box Elder Ditch Company ( "BEDC ") (WDID 0300926) <br />shares that were part of 64 shares historically used to irrigate the property known as the John Weitzel <br />Farm, which is the site of the Timnath- Connell Pit. The primary source of replacement water for this <br />SWSP will be from recharge of 2.5 of these BEDC shares. The shares will be diverted into a recharge pit <br />(WDID 0302059) located on the Timnath- Connell site. The recharge pit was constructed in an area of the <br />mining site that was previously excavated for sand and gravel mining. The remaining 1.5 BEDC shares <br />not used for recharge will continue to be used to irrigate the portion of the John-Weitzel Farm still in <br />agricultura(i production. <br />The i,diversions available at the farm headgate for the 4.0 BEDC shares used on the John <br />Weitzel property were estimated to total 364.19 acre -feet per year, and the historical consumptive <br />use of the 4.0 BEDC shares was estimated to be 168.91 acre -feet. This quantification is based on the <br />average headgate diversions for the Box Elder Ditch for the years 1950 to 2013, assuming 10% ditch <br />loss and 55% field efficiency for flood irrigation. Historic consumptive use was determined as the <br />i <br />