2008-07-07_HYDROLOGY - M2008006 - Laserfiche WebLink

Home Browse Search

Mr. Richard Raines July 2, 2008 Page 2 discharged into the settling ponds and will percolate into the ground. The IDS AWAS stream depletion model was used to determine the lagged depletions to the Cache La Poudre River. The following parameters were used in the model: transmissivity (T) = 45,000 gallons per day per foot, specific yield (SY) = 0.2, the distance from the Cache La Poudre River to the edge of the alluvium = 4,300 feet, and the distance from the centroid of the exposed surface water areas to the Cache La Poudre River is approximately 600 feet. Because this is a new proposed mining operation, no ground water was exposed at this location prior to January 1, 1981. The stream depletion model shows that the Applicant must replace 7.5 acre-feet for the period of August 2008 though July 2009 and 8.9 acre-feet from August 2009 through July 2010. You have provided a monthly breakdown of the maximum annual depletions totaling 1.2 acre-feet of evaporative loss from a maximum of 0.49 acres of exposed ground water at the settling ponds and dewatering trenches, 2.0 acre-feet of water loss due to dust suppression, and 6.0 acre-feet of water losses associated with the extraction of an estimated 202,500 tons of aggregate from below the water table. No phreatophyte credit has been applied to this plan. Replacements In the Future, Connell Resources, Inc. plans to utilize two shares of the New Cache La Poudre Irrigation Company ("New Cache") to make replacement for depletions caused by the SerFer Pit mining operation, and the Applicant is currently working with the Town of Windsor to trade the New Cache shares for augmentation credits. Until an agreement is reached between Connell Resources and the Town of Windsor, the operator proposes to provide replacement for the actual operational depletions from excess credits associated with a recharge project involving 2.0 shares of the Box Elder Ditch as previously approved for replacement use in conjunction with the Applicant's other gravel pit operations including the Stute Pit (M-81-007), Timnath-Connell Pit (M-99-050) and a newly proposed SWETS Pit (Unknown DRMS No.). The shares will be diverted into a recharge pit located on the Timnath-Connell site. The evaporation losses for the recharge pond are covered by the combined plan for the Stute Pit (M-81-007) and Timnath-Connell Pit (M-99-050). In 2008 and 2009, two shares will be diverted into the recharge pond to provide replacement water for the combined plan (Stute Pit and Timnath-Connell Pit) and SWETS Pit and this plan. Connell Resources, Inc. owns 4.0 shares in the Box Elder Ditch that were historically used to irrigate the property known as the John Weitzel Farm, which is the site of the Timnath-Connell Pit. Connell Resources also owns 0.5 shares of the 3.5 shares Box Elder Ditch shares that were historically used to irrigate the property known as the Robert Weitzel Farm, which is now divided into two mining sites (Stute Pit and Weitzel Pit). The historical consumptive use of 4 Box Elder Ditch shares used on the John Weitzel property is estimated to be 170.72 acre-feet and the return flow obligations for 4 shares for October through April is 89.52 acre-feet. This quantification is based on the average headgate diversions for the Box Elder Ditch for the years 1950 to 2004 assuming 10% ditch loss and 55% field efficiency. The pro-rata historical consumptive use credit for the two shares is 85.36 acre-feet and the pro-rata return flow obligation for the two shares for October through April is 44.76 acre-feet. The 85.36 acre-feet was determined as the lesser number from the water available for crop consumption (diversion available at the farm headgate multiplied by the 55% field efficiency) and the potential crop consumptive use values determined from the South Platte Consumptive Use Model (see Table 3A). A total of 246.64 acre-feet were diverted into the recharge site between April 18 and July 5, 2007. Connell Resource will divert the full farm