2011-08-30_HYDROLOGY - M1999050 - Laserfiche WebLink

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Mr. Jared Dains Timnath - Connell Pit -M99 -050 August 29, 2011 Page 2 estimated to be approximately 39 inches /year and with an annual effective precipitation amount of 0.8 feet (9.6 inches), net annual evaporation is estimated to be approximately 2.4 acre -feet per acre (29 inches). For the 8.0 acres of ground water exposed at this site, annual net evaporation is estimated to be 19.5 acre -feet. The total annual consumptive use from evaporation and operational uses at the site is 26.2 acre -feet. The lagged depletions from the Timnath - Connell Pit were estimated by the Applicant's consultant using the Glover method, with an estimated distance from the centroid of the pit to the no flow aquifer boundary (which is perpendicular to the point of impact) of 8,500 feet, an estimated distance from the centroid to the Cache la Poudre River of 2,500 feet, an aquifer transmissivity of 50,000 gpd /ft, and a specific yield of 0.2. For purposes of this SWSP the assumed distance from the centroid of the pit to the no flow aquifer boundary will be accepted, however for any future approval the distance must be amended to be consistent with the distance to the no flow boundary used for calculating lagged recharge accretions. The total lagged stream depletions for this plan are shown in the attached Table 2. Replacements The source of replacement water for this combined plan will be from 2.0 Box Elder Ditch shares (WDID No. 0300926). The shares will be diverted into a recharge pit 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 evaporation losses listed in Table 2 for the Timnath- Connell Pit include the evaporation losses from the recharge pond. Over the plan period, 2.0 shares will be diverted into the recharge pond to provide replacement water. 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 0.5 shares used on the Robert Weitzel property is not to be used for this plan. The historical consumptive use of the 4.0 Box Elder Ditch shares used on the John Weitzel property is estimated to be 170.72 acre -feet and the return flow obligations for these 4.0 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 2.0 shares is 85.36 acre -feet and the pro -rata return flow obligation for the 2.0 shares for October through April is 44.76 acre -feet. A total of 246.2 acre -feet were diverted into the recharge site between May and September 2010 (Appendix B). Connell Resources began diverting the full farm headgate delivery of the 2.0 shares in April 2011. Applegate provided a table with actual diversion data through July 2011, and projections through March 2012. The monthly timing of 261.38 acre -feet (full farm headgate delivery of the 2.0 shares) was used in the recharge model to determine the recharge accretion credits through March of 2012. The lagged accretions to the Cache la Poudre River are estimated to total 255.75 acre -feet for April 2011 through March 2012 (includes carry over from recharge in previous years). The summer and winter return flow obligations from the 2.0 Box Elder Ditch shares will be maintained by this substitute water supply plan.