2011-01-10_HYDROLOGY - M2001022 - Laserfiche WebLink

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Ms. Cristyn R. Radabaugh Green/Croissant Pit, M-2001-022 January 10, 2011 Page 3 of 6 100 gallons per minute, therefore long-term dewatering was estimated at 75 gpm for the purposes of this SWSP. During dewatering, water will be returned to the Big Thompson River at the same rate as dewatering occurs, but will result in delayed depletions to the stream system. The following parameters were used in the IDS AWAS stream depletion model determine the lagged depletions to the Big Thompson River: transmissivity (T) = 50,000 gallons per day per foot, specific yield (SY) = 0.2, the distance from the Big Thompson River to the edge of the alluvium = 2,820 feet, and the distance from the centroid of Cell 4 area to the Big Thompson River is approximately 1,100 feet. The lagged depletions and offset for the return of water to the stream due to dewatering are shown in the attached Table 4. The anticipated annual net depletions for this plan are shown as 74.19 acre-feet for 2011 and 94.14 acre-feet for 2012. Replacements The proposed source of replacement water for this pit is fully consumable effluent leased - -- - from-the--City-of Loveland-and-made-available at its-wastewater treatment.. plant_(WDID____ __- 0402300). Monthly replacements are calculated as total monthly depletions plus 1.85 percent transit losses from the Loveland wastewater treatment plant to the pit site. The long-term replacement requirement will be provided by the 25-year lease with the City of Loveland, which expires December 31, 2022. A copy of the lease is attached to this letter. Also, in a letter dated November 18, 2008 the City of Loveland indicated that the City is prepared to deliver up to 200 acre-feet in 2009 and each year throughout the lease term. Of this water, 6.38 acre-feet have been committed to an approved SWSP for the Bokelman-Walters Pit (M-06-080). The remaining leased water is available for replacements under this SWSP, as shown in Table 5. The monthly lagged depletions and replacement requirements are found on the attached Table 4. Conditions of Approval I hereby approve the proposed substitute water supply plan in accordance with §37-90- 137(11), C.R.S. subject to the following conditions: 1. This plan shall be valid for the period of January 1, 2011 through December 31, 2012, unless otherwise revoked, modified, or superseded by decree. If this plan will not be made absolute by a water court action by the plan's expiration date, a renewal request must be submitted to this office with the statutory fee (currently $257) no later than November 15, 2012. 2. A well permit was obtained for the current use and exposed pond surface area of the gravel pit in accordance with §37-90-137(2) and (11), C.R.S., permit no. 67817-F. 3. The total surface area of the groundwater exposed at the site must not exceed 26.70 acres from January 2011 through March 2011, and 26.80 acres from April 2011 through December 2012, which results in a maximum evaporative annual loss at the Green/Croissant Pit of 67.51 acre-feet for 2011 and 67.54 acre-feet for 2012. 4. The annual total product mined at the Green/Croissant Pit shall not exceed 100,000 tons per year resulting in 2.95 acre-feet of water lost with the mined aggregate, 7.06 acre-feet of