2012-09-06_REVISION - M2008070 (21)

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wash plant. Consumptive water use falls under the jurisdiction and control of the State Division of Water Resources, which agency will ensure that consumptive uses do not exceed the established legal water rights and consumption now occurring via agricultural flood irrigation on the Property. Concerning water rights, the White River is unique in Colorado in that it is under - adjudicated, meaning that its water supply exceeds the water right demands legally decreed. In such instances, it is not necessary to file change cases with the Water Court to convert historic agricultural water rights to industrial rights. Also, since the Love's will continue with traditional agricultural production on their property during and after gravel production has ended, the change of use for gravel production would only be considered temporary in any event. In order to service the needs of employees around the site, the company will contract with a local septic service to maintain portable "port-o-johns" on the site. For the operation's office facility, the company will have a small septic system and leach field engineered and appropriately permitted with the County. In regard to water, one other potential affected environment concerns subsurface groundwater. In particular, the potential for contamination of wells from surface activities in the gravel pit was an issue identified by the County. A review of records from the Division of Water Resources confirms there are no wells within 600 feet of the proposed gravel pit. Further, the geological formation immediately below the gravel deposits is known as Green River Shale, which is a relatively impermeable formation that should prevent surface waters and any potential contaminants from infiltrating any aquifers that may lie below. Since the gravel pit will necessarily be a shallow mine due to the fact that alluvium deposits throughout the Piceance Basin average about 14 feet in depth (though ranging from 12 -90 feet in places) (Topper et al 2003), the possibility of contaminating domestic groundwater supplies is extremely remote. Environmental Consequences of Proposed Action: Operation and maintenance of the gravel pit and associated access roads will cause surface disturbances to approximately 115 acres of upland terraces in Phase 2, which creates the potential for erosion and sediment transport to nearby watersheds, particularly the White River. However, given the Stormwater permitting requirements imposed by the State to regulate such potential occurrences, the proposed action should not cause a significant threat to surface water quality. Likewise, the absence of wells near the proposed gravel pit and the presence of the relatively impermeable Green River formation immediately below the gravel deposits should ensure no potential for groundwater contamination from operations at the facility. Standard sanitary management practices for operation and maintenance of port-o johns and an appropriately engineered and permitted septic system for the office will prevent any possible contamination of surface or groundwater supplies. Mitigation: The following items should be added as conditions of approval. 1. State stormwater regulations and required SWMP document shall be incorporated to this EA by reference, and shall serve as assurance that surface runoff and potential watershed contamination will not occur as a result of the proposed action. Environmental Solutions, Inc. Page 8 of 30 March 09