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Frey Hatchery Pit, M2014-043 Page 3 of 6 December 11, 2017 Water for gravel washing and dust control wilt be provided by water pumped from the pit for dewatering. The estimated water used for dust suppression during the first two years of operation total 1.0 acre-foot/year. The total consumptive use at this site is 18.43 acre-feet for the first year of operation and 14.78 acre-feet for the second year of operation. You have provided a monthly breakdown of the annual depletions, which include 2.75 acre-feet/year of net evaporative loss from 1 acre exposed water surface area, 14.68 acre-feet of water lost with the mined product during the first year, 11.04 acre-feet of water lost with the mined product during the second year, and 1 acre-foot/year of water used for dust control, as shown on the attached revised Table 2. There are several lined gravel pits located between the Frey Hatchery Pit and the South Platte River. No drains were constructed between or around the pits to facilitate the passage of ground water that may mound up gradient of the lined pits. According to the information provided, the Frei Hatchery pit depletions wilt affect the Bull Seep because the water will not make it to the South Platte River due to the existing gravel pit liner between the river and the pit. The But[Seep, is a natural spring-fed tributary to the South Platte River that runs along the west side of the Frei Hatchery Pit permitted area. The seep is up gradient of the lined gravel pits below and travels approximately 1.75 miles north before discharging into the South Platte River. Dewatering is anticipated from Phase 1 of this operation to facilitate dry mining operation. Water will be pumped from the Frei Hatchery Pit into Bull Seep at a location near the center of the shared quarter/quarter line between the NW1/4 of the SW1/4 and the SW1/4 of the SW1/4 of Section 20, Township 2 South, Range 67 West of the 6`h P.M. That location is shown on the attached Figure 3. The dewatering water at the Frei Hatchery Pit will make it to the South Platte River near the McKay Road Bridge, in the SE1/4 of the SW1/4 of Section 17, Township 2 South, Range 67 West of the 6t' P.M. as shown on Figure 3. A Glover analysis was used to determine the tagged depletions from dewatering, evaporation and operational losses to the Bull Seep. The aquifer characteristics used in the model well for the exposed surface area, dewatering and the water lost with the mined product are: transmissivity(T) = 87,000 gallons per day per foot, specific yield (SY) = 0.2, the distance from the centroid of the exposed ground water to the stream = 350 feet, and the location of the parallel impermeable boundary was estimated to be 12,900 feet from the stream, The total lagged depletions from the first year of operation are equal to 16.77 acre-feet and the total Lagged depletions from the second year of operation are equal to 14.33 acre-feet, as shown on the attached revised Table 2. Replacements Out-of-priority depletions associated with the mining operation at this site will be replaced using fully consumable municipal return flows leased from the City of Aurora ("Aurora"). A copy of the lease with Aurora was provided to this office with this SWSP request and is attached to this letter. The term of the lease is from June 1, 2017 through May 31, 2019. An updated lease with Aurora was provided to this office on December 5, 2017. The updated lease covers depletions from October 2017 through September 2019. Under the lease, water will be delivered to the outfall of the Robert W. Hite Treatment Facility (aka Metro Sewer, WDID 0200700) located on the South Platte River. Aurora may alternatively deliver water at other points along a reach of the South Platte River beginning at or below the Hite Treatment Facility and continuing downstream to a point at or above the location where the South Platte River crosses the East 104`h Avenue. The Applicant must notify the water commissioner at least 48 hours prior to making replacement deliveries at a location other than the Hite Treatment Facility.