2008-01-14_HYDROLOGY - M1978052 - Laserfiche WebLink

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Michelle L. Hatcher Page3 January 12, 2008 67 West, 6th P.M. However, according to the additional information submitted on December 17, 2007, due to resent mounding issues associated with the Zigan Reservoir, Lafarge is unable to deliver their 25 Fulton Ditch shares into Zigan Reservoir at this time. Therefore, the Fulton ditch shares will not be relied upon as a replacement source in this SWSP. Lafarge would however like to keep the Fulton shares in the SWSP renewal request as a backup rep-acement source for possible use in the future. The historic use of the 25 Fulton ditch shares yields 43.89 acre-feet of water during April through October while generating 5.25 acre-feet of return flow obligation during November through March. This quantification is based on the technique used in the March 24, 1999 approval for the Fulton Lakes Pit, where the historic consumptive use values were determined using an analysis decreed in case number 82CW393. In this approach, headgate diversions were based on average monthly values for the period of 1976-1988 and a 10% conveyance loss was assumed as well as a farm efficiency of 50%. The return flow obligations, which were not addressed in the above decree, were calculated for this plan based on the assumption that all water diverted but not used by the crops is returned to the stream system through deep percolation. The historical consumptive use and net consumptive use credit realized at the river from recharge of the Fulton Ditch shares is shown on attached Table No. 2. The Applicant has an agreement with the City of Aurora ("Aurora") whereby Aurora will continue to make releases of reusable effluent up to a maximum volume of 249 acre-feet for the Lafarge SWSPs. In addition to this SWSP, the Aurora effluent is also used to replace depletions resulting from Lafarge's Lupton Lakes Resource Pit. Of the 249 acre-feet available to Lafarge 136.2 acre-feet will be used for augmentation purposes under that SWSP. Therefore, approximately 112.8 acre-feet remains of the total Aurora lease, which is more than sufficient to augment the depletions under this SWSP. The applicant will account for a transit loss of 0.5% per mile from the Metropolitan Waste Water Treatment Plant to the gravel pit sites. The transit losses for each site are shown in the table below. For purposes of the SWSP request, an average 5% transit loss was used, which is conservative given the estimated depletions at each site. Point of Re lacement Distance From Re lacement Source mi Transit Loss From Replacement Source Howe Pit 7 3.5% Tanabe Pit 7 3.5% Dunes Develo ment 7 3.5% Mann Lakes 8 4% Sta ecoach 8 4% Ft. Lu ton Pit 19 9.5% The total lagged mining depletions and replacements are shown on attached Table no. 3. Conditions of Approval I hereby approve this substitute water supply plan, in accordance with Section 37-90- 137(11), C.R.S., subject to the following conditions: 1. This SWSP shall be valid for the period of November 1, 2007 through October 31, 2008, unless otherwise revoked, modified, or superceded by decree. If this plan will not be made absolute by a water court action by the plan's