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Todd Williams Kauffman No. 1 SWSP January 7, 2013 Page 2 and an overall drop in water levels, the pit is now at 34.9 acres and falls within the pre -81 boundary previously set. Therefore, evaporative depletions will not be assessed during this SWSP approval period. The exemption from augmentation requirements for the pre -81 area is tied to the physical location previously identified on Map 3 of the 2012 SWSP and may not be re- allocated to other areas of ground water exposure within the gravel pit permit boundary. Any pre -81 area that is backfilled will lose the pre -81 exemption should it be excavated in the future. Additionally the backfilling of a pre -81 area shall not create a credit to be used elsewhere. The Applicant projects using up to 5.37 acre -feet of groundwater for dust control use as shown in Table 3. Although the City of Loveland used 0.1 acre -feet of water for irrigation in September 2012, it is not anticipated for this use to continue in 2013. The monthly depletions to the Big Thompson River were lagged from the pit site using the AWAS program developed by the IDS Group at Colorado State University. The parameters used in the model were an estimated distance from the centroid of the exposed water surface area to the Big Thompson River (X) of 550 feet, an estimated distance from the river to the no flow aquifer boundary (W, measured perpendicular to the point of impact) of 4,000 feet, an aquifer transmissivity (T) of 50,000 gallons per day per foot, and a specific yield (S) of 0.2. For the sake of simplicity in estimating lagged evaporative depletions from 2012 the Applicants consultant lagged the 2012 evaporation using the 2012 SWSP projections of 3.8 acres even though it was completely backfilled at some point within 2012. In total the lagged stream depletions are estimated to be 9.14 acre -feet during the term of this approval, as shown on the attached Table 5. Replacements Replacement water for this pit will continue to be made available throughout the year from a lease of 65.0 acre -feet of fully consumable water from the City of Loveland ( "Loveland "). This lease also applies to losses at another gravel pit, Wagner /Kauffman Pit #3 (M- 1999 -069, WDID 0403008). A copy of the lease associated with the mining operation is attached to this letter. The duration of the lease is from January 1, 2013 through December 31, 2015. A 4 percent transit Toss from Green Ridge Glade Reservoir to Kauffman Pit has been applied to the delivery of the replacement water. Under the terms of the lease, replacements can be made using a variety of water owned by Loveland including, but not limited to, Windy Gap reusable effluent, Loveland Storage Reservoir water as decreed in case no. 82CW202A, and Colorado Big Thompson Project ( "C -BT ") water. In the event that the City plans to use C -BT water as a replacement source, the City shall comply with the Interim Rule issued by the Northern Colorado Water Conservancy District ( "Northern District ") in May 2005, regarding the use of Colorado -Big Thompson ( "CBT ") Project water in substitute water supply plans. Prior to the use of C -BT Project water, the City is required to notify this office, the division engineer and the water commissioner of the amount of C- BT Project water dedicated to this plan and provide a copy of the Northern District's approval letter as required by paragraph I(g) of the Northern District's May, 2005 Interim Rule. The monthly depletion and replacement requirements are indicated on the attached Table 5. 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 January 1, 2013 and shall be valid through December 31, 2013 unless otherwise revoked or modified. If this plan will not be made 4