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:- EJ{HIB[T "G" WATER INFORMATION The gravel mining operation is expected to intercept groundwater. The proposed gravel mining operation site would be situated over the unconfined aquifer tributary to the Rio Grande River in the San Luis Valley of southern Colorado. A river and three surface water canals are in the vicinity (within a square mile) of the proposed mining site although the operation is not expected to directly affect any of the surface water features. These surface water features include the Rio Grande River, the Fish Ditch, the Rio Grande Canal and the Billings Ditch. A map has been included showing all water courses, ditches, and wells on the affected land and on adjacent lands. The mining operation shall not introduce pollution to either surface or groundwater. The open gravel pits shall intercept ground water. No dewatering operations shall be utilized. During operation, water from the gravel pit shall be used to wash the gravel. Once used, this wash water shall be returned to the gravel pit. Since the gravel material being washed is consistent with ground material, the washing process shall not introduce any contaminants that the ground water is not already in contact with. No additional products (floatation aids or petroleum products) shall be introduced in to the wash water. After operation, the gavel pits shall be left open creating recreational lakes. Project water requirements shall be primarily the amount of augmentation water required to offset ground water evaporation from the exposed surface azea. During the development phase, no water shall be required by the project. During the mining operation, groundwater from the pit shall be required to wash the gavel. Washing requirements are estimated at 1.2 acre-ft/yr per acre-ft of mined material. This water is non-consumptive and shall be returned to the gravel pit once used. No dewatering operation shall be utilized. The primary water requirement of the operation is to replace exposed ground water surface evaporation. In accordance with Section 37-80-120 C.R.S all post-December 31, 1980 groundwater exposure from gravel pits must be augmented to replace the surface evaporation from the exposed groundwater. The applicant's surface water from the Fish Ditch and/or Rio Grande Canal shall be used to augment ground water surface evaporative losses from the pit. In accordance with the Colorado Division of Water Resources and an application for change in water right to water court that has not yet been finalized, the applicant will dry up 2.34 to 2.74 acres of pasture land for each acre of gravel pit surface area. The range is dependent on assumptions regarding surface water evaporation rates and crop evapotranspiration rates that must be worked out with the Colorado Division of Water Resources. Once the pit totals 100 acres, the amount of pasture land that shall be dried up totals 234 to 274 acres.