2009-12-15_HYDROLOGY - M1981022 - Laserfiche WebLink

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a Ms. Sira W. Sartori Page 2 G.L. Pit Substitute Water Supply Plan (DRMS# M -81 -022) December, 15 2009 Depletions The only consumptive use associated with the G.L. Pit site will be from evaporation of exposed groundwater. As mentioned above the current exposed surface area at the G.L. Pit is 4.2 acres. Total estimated annual consumptive use for this plan is 5.9 acre -feet of evaporation from 4.2 acres of exposed water surface area which also include a phreatophyte credit. For the 4.2 acres, an evaporative value of 16.76 inches was used. The evaporative depletions from the 4.2 acres are 5.9 acre -feet. The G. L. Pit is located approximately 1700 feet from the Cache La Poudre River, thus depletions were not assumed to be instantaneous and have been lagged back to the Cache La Poudre River. You have provided a monthly breakdown of the annual lagged depletions totaling 5.9 acre -feet of evaporative loss. The amount of lagged depletions is'6.2 acre -feet which include the post - pumping depletions of the area that has been backfilled. Replacement The proposed source of replacement water for this pit is a lease of fully consumable water from the Tri- Districts. The lease is for the period of November 2009 through October 2010. A copy of the Tri- Districts lease was provided to this office on October 27, 2009 and is attached to this letter. The replacement water will originate from Sand Creek Ditch, which can only deliver transbasin water to Eaton Reservoir during the warm months of the year. The Tri- Districts have water stored in low elevation reservoirs to make replacements during all months of the year in coordination with the Poudre River water commissioner. The amount of replacement water leased from the Tri- Districts also includes a 7.8 percent transit loss from the Sand Creek Ditch. The transbasin Sand Creek Ditch water is transported over Boulder Ridge in the Wilson Ditch and stored in the Eaton Reservoir. Releases made from Eaton Reservoir travel approximately 50 miles to the mouth of the Poudre Canyon. The monthly depletions and replacement requirements are found on the attached Table I. 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 is.approved with the effective date of November 1, 2009 and shall be valid through October 31, 2010 unless otherwise revoked or modified. If the groundwater pond has not been completely backfilled and lagged depletions to the stream system have not ceased by the plan's expiration date, a renewal request must be submitted to this office with the statutory fee (currently $257) no later than September 15, 2010. 2. Well permit no. 42334 -F 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. Applicant shall operate the gravel pit in accordance with the conditions of approval of permit no. 42334 -F. 3. The total surface area of exposed groundwater must not exceed 4.2 acres resulting in 5.9 acre -feet of evaporative loss. Should the total consumption at the pit exceed this amount, The Applicant is required to file an amendment with this office. 4. Approval of this plan is for the purpose as stated herein. Any additional uses for which the