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<br />Appendix G-1 contains data obtained from the State Engineer's office for all known water <br />rights and well permits located in the area. All well permits and decreed wells aze numbered <br />and correspond to the locations of wells shown on Figure G-1. The locations for the wells <br />are based on the State Engineer's and are not based on actual field locations. There is also <br />some evidence that a significant number of these permits, although listed, are no longer active <br />wells. <br />The project lies in the Valley fill deposit for the Brighton Reach of the S. Platte River. The <br />Valley fdl aquifer in this general location is approximately 6,500 to 7,000 feet in width. <br />The volume of saturated thickness of the aquifer varies with depth to bedrock, but <br />generally ranges between 20 to 40 feet as characterized by USGS. This would indicate <br />the aquifer characteristics agree with existing mining operations in the area that have <br />been done to date. The aquifer generally has a permeability of about 7,000 to 9,000 <br />gpd/square foot, and a coefficient of storage of 0.09. The hydraulic gradient of the <br />groundwater can be estimated using the gradient of the river valley in this vicinity <br />which is 0.00152 ft/ft. Flow direction of the groundwater through this aquifer is on a <br />diagonal that moves downstream. It generally reflects the return flow patterns from <br />irrigated lands in the area or sources of seepage such as precipitation, irrigation <br />ditches, recharge projects, etc. Sources will change over time, particularly with respect <br />to irrigation practices. Irrigable land that is taken from service or ditch shares that are <br />transferred to other uses will have an impact on the groundwater table. These impacts <br />would be unknown and well beyond the scope of this permit. Item #22 This is an alluvial <br />aquifer that is unconfined and consists of the sand and gravel that is being mined. The limits <br />of the aquifer correspond roughly to the limits of the floodplain. The depth of the aquifer <br />ranges from approximately 10' to 50' depending upon the conformation of the underlying <br />bedrock. It is estimated that bedrock lies between 25' to 35' below the proposed mining site. <br />The underlying bedrock is the Denver formation, which is a blue claystone-siltstone formation <br />that is several hundred feet thick. This formation is almost totally impermeable. There are <br />no known intrusions into the formation on this property. The upper three feet is weathered <br />and has some minor fracturing. The unweathered shale is competent as a seepage barrier. The <br />claystone in a decomposed form is an excetlent impermeable zone material in the construction <br />of reservoir liners or dams. The consistency of bedrock will be monitored during the mining <br />operation to determine if there are any geologic anomalies that create seepage paths into the <br />proposed reservoir. There are several non-tributary aquifers that underlie the Denver <br />formation. These include the Upper and Lower Arapahoe and the Laramie Fox-I-tills. These <br />aquifers are confined in this area and will not be affected by the proposed mining operation. <br />3 <br />