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2023-2024 GSL Sand 6t Gravel Substitute Water Supply Plan Page 3 of 9 <br /> November 14, 2024 <br /> to evaporation of groundwater exposed at the site has been calculated to be 2.85 acre-feet <br /> per acre or 2.46 acre-feet for this SWSP period. A summary of the mining depletions is shown <br /> on attached Table 1. <br /> The Integrated Decision Support Group Alluvial Water Accounting System ("IDS-AWAS") <br /> model was used with the alluvial aquifer boundary condition to lag depletions to the South <br /> Platte River. The parameters shown in Table A below were used in the model. Lagged <br /> evaporative depletions are 2.47 acre-feet for this SWSP period, as shown on the attached <br /> Table 3. <br /> Table A: IDS-AWAS Parameters for the Gravel Mine <br /> X - Dist to river W - Boundary Dist Harmonic <br /> (feet) (feet) Transmissivity Specific yield <br /> (gpd/ft) <br /> 2,295 3,836 63,000 0.2 <br /> Replacements <br /> The replacement source for this plan period is fully consumable water leased from Aurora. <br /> The fully consumable water will be released to the South Platte River at the outfall of the <br /> Metro Wastewater Reclamation District's Robert W. Hite treatment facility ("Metro Sewer," <br /> WDID 0200700). Metro Sewer is located approximately 10.78 miles upstream of the site. As <br /> such, an irrigation season (April through October) transit loss of 5.39% (0.5% per mile) and a <br /> non-irrigation season (November through March) transit loss of 2.7% (0.25% per mile) will be <br /> assessed on all releases. These transit losses are subject to change by the Water <br /> Commissioner or Division Engineer. <br /> A copy of the signed lease agreement dated November 24, 2020 is attached. The term of the <br /> lease is for the period of November 1, 2020 through October 31, 2021 and is renewable for <br /> up to five additional one-year extensions provided by written notification from Aurora. <br /> According to the attached letter from Aurora (Aurora lease extension) dated September 25, <br /> 2024, the final one-year extension has been granted for the period of November 2024 <br /> through October 2025. The proposed replacement schedule is provided in Exhibit A of the <br /> delivery schedule provided with the Aurora lease extension. Total replacements to be <br />