2008-01-07_HYDROLOGY - M1977439 - Laserfiche WebLink

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Mr. Richard T. Raines January 4, 2008 Page 2 Overland Ponds Site 5.46 0.0 0.0 5.46 No North Taft Hill 29 73 0.0 0.0 73 29 No Expansion Site . Total 63.13 14.7 2.0 79.88 The only consumptive use at the North Taft Hill Expansion Site and the Overland Ponds Site is the evaporation from exposed ground water. The mined material from the Overland Ponds Site will be conveyed to the existing facilities at the Home Office Pit for processing. Therefore the 14.7 acre-feet associated with mining of up to 500,000 tons of aggregate per year and 2 acre-feet per year of water used for dust control listed in Table B for the Home Office Pit will in fact be from the Overland Ponds Site. Mining at the North Taft Hill Expansion Site ended January 2005. This site was continuously dewatered until the end of January 2005. After January 2005 the lake was allowed to fill, as the mining operation begun at the nearby Overland Pond Site. All post pumping depletions at the North Taft Hill Expansion Site were replaced under the terms of the previous plan. The source of replacement water for this combined plan will be from 5.75 Taylor and Gill Ditch shares. The shares will be diverted into a recharge pit located on the Home Office site. The evaporation losses from the recharge pond during this approval period are estimated at 2.58 acre-feet (Table 1). In 2006 and 2007 the 5.75 Taylor and Gill Ditch shares were diverted into the recharge pond for lagged replacement water. The 5.75 shares will be diverted in the recharge pond again in 2008 to provide replacement water for this combined plan. The 5.75 shares were historically used to irrigate 104.5 acres of pasture grass, all of which have been taken out of production. The historic consumptive use of the 5.75 shares was determined to be 122.8 acre-feet (includes consumptive use and return flows). The 5.75 shares will be diverted into the recharge pit each irrigation season. The return flow obligations from the Taylor and Gill Ditch will be maintained by the recharge plan. The attached Table 3 shows the farm headgate delivery of 5.75 Taylor and Gill Ditch shares. Lafarge plans to divert the full farm headgate delivery of 240.31 acre-feet into the recharge site each year (Table 3). A total of 50.4 acre-feet were diverted into the recharge site between May 9 and September 25, 2007. Because of the small volume of recharge in 2007, Lafarge had a shortfall of 137.2 acre-feet from April 2007 through October 2007. Therefore Lafarge secured a lease with the City of Fort Collins to replace the monthly shortfall of 137.2 acre-feet. A copy of the lease with the City of Fort Collins was submitted to this office on December 6, 2007. Based on the information received from the water commissioner, the 137.2 acre-feet were released from Joe Wright Reservoir. Lafarge will divert the full farm headgate delivery of the 5.75 Taylor and Gill Ditch shares starting in April 2008. Accordingly, the monthly timing of 240.32 acre-feet (full farm headgate delivery of the 5.75 shares) was used in the recharge model to determine the recharge accretion credits for 2008. The lagged accretions to the Cache la Poudre River are estimated to total 188.48 acre-feet for this approval period (includes carry over from recharge in previous years). During the Water Year 2008, a lease from the Tri-Districts will make additional replacements for the months with insufficient recharge credits. The total amount of water required (including 7.8 percent transit losses) is 22.05 acre-feet. A copy of the lease with the Tri-Districts was provided to this office on December 6, 2007 and is attached to this letter.