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Transit Mix Concrete Co. <br /> 6. Groundwater <br /> A summary of groundwater resources and an evaluation of potential impacts resulting from <br /> quarrying prepared by Hydro-Logic Solutions, Inc. is included as Attachment G-2. Transit Mix <br /> commissioned a drilling and multi-level groundwater monitoring installation program in the <br /> summer of 2017 to characterize further the groundwater resources in the Quarry area. This <br /> program was designed and overseen by hydrogeologists from Hydro-Logic Solutions, Inc. and <br /> Norwest Corporation. <br /> a. Geologic Setting <br /> Available USGS geologic mapping2 indicates that the eastern portions of the Ranch property in <br /> Sections 15, 22 and 23 are partially underlain by the sedimentary Fountain Formation (a bedrock <br /> formation containing water-bearing sandstone units) and that the remainder of the Ranch <br /> property is underlain by granite, diabase, diorite, granodiorite and quartz monzonite, collectively <br /> referred to as "granodiorite" in this discussion. The elevated ridges south of the Little Turkey <br /> Creek, as illustrated in Figure C-3, have exposed on surface uplifted basement rocks comprising <br /> mostly granite, diabase, and granite gneiss. These rocks are similar to what is described as <br /> granodiorite from detailed mapping completed by the USGS on the Cheyenne Mountain quad <br /> (Rowley et al., 2003) located east of the property. These two very different rock types (Fountain <br /> Formation versus granodiorite) are separated by north-south oriented high-angle geologic faults, <br /> bounded by the East Fault on the east and the West Fault on the west, as shown on Figure G-1. <br /> These major geologic structural features have a significant hydrogeological influence on the <br /> ground water systems in the granodiorite materials and the sedimentary formations. The <br /> proposed Quarry location in Section 16 is located in an area completely underlain by the <br /> granodiorite material. <br /> Stream geomorphology and field mapping indicate that the Little Turkey Creek channel is <br /> structurally controlled by narrow fracture zones trending northwest to southeast along the Little <br /> Turkey Creek valley. These fracture zones trend perpendicular to the more significant <br /> north-south oriented high-angle thrust faults, shown on Figure G-1, that also influence stream <br /> geomorphology. A small amount of quaternary gravel and terrace alluvium has been mapped in <br /> conjunction with Little Turkey Creek. <br /> The 2017 drilling program identified the existence of saturated groundwater conditions within the <br /> granodiorite rocks above the level of Little Turkey Creek. Groundwater in the western portion of <br /> the Ranch occurs within fractures in the granodiorite basement rock. Observations of geologic <br /> core, optical/acoustic imaging logs, and HydroPhysical data collected during the drilling program <br /> indicate that fractures within the granodiorite rock, below the shallow weathered zone, are tight <br /> and yield very low rates of water inflow into open boreholes. Domestic water supply wells <br /> Z Geologic Map of the Pueblo 1-degree X 2 degrees quadrangle,south-central—1976 and the Geologic Map of the <br /> Cheyenne Mountain Quadrangle, El Paso County,Colorado—2004. <br /> Hitch Rack Ranch Quarry Permit Application <br /> October 3,2017 G-27 <br />