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1 . General Location and Description <br /> 1.1 Location and Description of Property <br /> Holcim-WCR, Inc. operates the Morrison Quarry (Site), a hard rock aggregate quarry, located <br /> within the Town of Morrison limits and approximately one mile south of the intersection of <br /> Colorado State Highway 8 (CO-8) and Colorado State Highway 74 (CO-74). The Site is <br /> approximately one mile north of the intersection of CO-8 and US Highway 285 (US-285) and the <br /> Red Rocks Country Club. The physical address for the entrance is 18131 CO-8 Morrison, <br /> Colorado 80465. The Site is situated in the Front Range foothills west of the Dakota Hogback <br /> geologic formation. Mount Falcon Open Space Park is located west of the Site. Areas <br /> immediately north and south of the Site are largely undeveloped. Areas immediately east of the <br /> Site are owned by Holcim-WCR, Inc and private owners who use the property for residential <br /> and rangeland purposes. The Site is located in Jefferson County and in Section 11, Township 5 <br /> South, Range 70 West. <br /> The Site operates under the Colorado Department of Reclamation, Mining and Safety (DRMS) <br /> permit M-1973-021 and has a total permitted area of 364.77 acres. The permitted mining area <br /> includes a 1.97-acre parcel with a water storage tank and a 27.5-acre water storage reservoir <br /> (Reservoir Site 11), both owned by the Town of Morrison. The Site also operates under the first <br /> amendment to the Planned Unit Development— Industrial (PUD-1) for the Town of Morrison <br /> which was completed in 1994 and revised in 1999. This report provides information on the <br /> proposed south quarry highwall diversion design necessary for the DRMS permit. <br /> The Site primarily consists of disturbed ground from aggregate mining operations, reclaimed <br /> areas consisting of grasses and shrubs, and undisturbed areas consisting of shrubs and trees. <br /> The Site discharges stormwater and process water under the Colorado Department of Public <br /> Health and Environment (CDPHE) General Permit COG500000 Discharges Associated with <br /> Sand and Gravel Mining and Processing, Certification COG500320 through five existing <br /> outfalls (see Appendix C). The five outfalls report to two major drainageways near the Site: <br /> Strain Gulch which flows into Bear Creek north of the Site, and an unnamed tributary to Turkey <br /> Creek to the south. The Site is not located near irrigation facilities, delineated floodplains, or <br /> flood hazard area delineation (FHAD) study areas. More detailed descriptions of the nearby <br /> major drainageways and Site drainage patterns are discussed in Section 2. Figure 1 shows the <br /> Site location, drainage paths, drainage features, outfalls, and the surrounding major <br /> drainageways. <br /> 1.2 Project Description <br /> This Phase III Drainage Report builds upon the data and recommendations made in the <br /> Morrison Quarry Phase II Drainage Report prepared for Holcim-WCR, Inc. (formerly Aggregate <br /> Industries) (Brown and Caldwell 2021). The main purpose of this report is to document the <br /> analysis and design of the Drainage Facility Design described in Section 4 of the Phase 11 <br /> Report, as updated in Section 4 of this Phase I I I Report. The analysis updates the hydrology <br /> for Drainage Areas 02, 03, and 04 only as documented herein. Analysis of drainage areas or <br /> facility design for other Drainage Areas are unchanged and description of these are carried <br /> forward largely unaltered from the Phase 11 Drainage Report. <br /> 1670 Broadway,Suite 3400,Denver,CO 80202-4824 hdrinc.com <br /> (303)764-1520 <br />