2020-12-08_REVISION - M2008078 (23)

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EXHIBIT G Water Information Introduction The West Farm Pit is located in the south '/2 of Section 26, south '/ of Section 27, south 'h of Section 28, south % of Section 29, north % of Section 32, southwest % and north '/2 of Section 33, north '/ of Section 34, north '/2 of Section 35, and the northwest '/4 of Section 36, Township 22 South, Range 46 West of the Sixth Prime Meridian, Prowers County, Colorado. The proposed mining site is located approximately '/2 mile east of the City of Lamar, and approximately % mile north of State Highway 50 as shown in Figure Exhibit G-1. The Arkansas River is approximately 1,000 feet north of the site, Willow Creek is adjacent to the southeast corner of the site, and the Lamar Canal is adjacent to the site. The operation will consist of sand and gravel production and will impact the Arkansas River in the form of depletions due to evaporation and operational losses associated with mining. Mining of the West Farm Pit will last for approximately 30 years. Once reclamation is complete, reservoirs will be created with a total surface area of approximately 1,036 acres. The depth to groundwater ranges from 10 to 24 feet. The site will be mined down to 20 to 70 feet, thus exposing groundwater to the atmosphere. This exposed groundwater, along with the operational losses associated with the extraction of sand and gravel deposits, will impact the Arkansas alluvial aquifer. These impacts will cause river depletions that must be augmented. To enable dry mining at the West Farm Pit, there will be a slurry wall installed around the perimeter of each phase/cell, dewatering trenches will be constructed within the perimeter of the slurry wall around the various phases of the site. These dewatering trenches will change in length throughout mining. The maximum length will occur when Phase 4 is completely mined, but before the reclamation has finished in that phase. The maximum size of dewatering trench will be 11,900 feet long and 5 feet wide, or 1.36 acres of exposed surface area. This water will be collected in various sediment ponds both within the mined phases and at the central sediment pond location. The total area of active sediment ponds will be 4.0 acres. After sediment has settled from the water it will be pumped into a farm ditch and discharged into the Arkansas River. As mining progresses, the dewatering trenches and discharge settling pond will shift as various cells are reclaimed. The gravel pit will be lined concurrent with mining per the reclamation plan. Water Requirements Water use at the West Farm Pit will include evaporation from exposed groundwater, dust control of haul roads and stockpiles, and water retained in material removed from the site. Evaporative Loss Evaporative losses are dependent on the exposed water surface area, which may shift throughout the mining operation, but will not exceed the maximum. Exposed surface area at the West Farm pit will include groundwater exposed in the dewatering trenches and discharge settling pond. The maximum exposed surface area at the site during mining is estimated at 5.36 -' JaT Consulting,Inc. Prowers Aggregate Operators, LLC. West Farm Pit—M-2008-078 DRMS 112 Permit Amendment Application