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<br />GRAND JUNCTION <br />' LINCOLN DeVORE, Inc. <br />GEOTEC(-INICAL ENGINEERS -GEOLOGISTS <br />1441 Motor St. TEL: (970) Z42-8968 <br />Grand Junction, CO 81505 FAX'. (970} 2dZ-1561 <br /> <br />' Grand Junction Pipe <br />PO Box 1849 <br />Grand Junction- CO R 1502 <br />November 12. 1997 <br />Re: Gravel Pit, SE corner of 23 and River Roads, Grand Junction, CO <br />' At .'our rcqucsL personnel from this office have completed a eround reconnaissance of the above referenced site <br />m order to determine the general geologic conditions and constraints relating to construction on the silt. The <br />proposed decclopment is open pit extraction of mineral aggregates. following are our findings. <br />' TRACT LOCATION & DESCRIPTION <br />' Thc tract tics in the northtccst Quarter of the southwest Quarter of Section 5, Township 1 S, Range 1 W of the <br />Ute Principal Meridian. Mesa Count}, Colorado. Thc tract is bounded on the north of River Road and on the <br />west b~ 23 Road. Gravel extraction has occurred south and west oC Ihis site, immediately adjacent to the <br />Colorado Ricer. Thc tract is within the corporate limits of the City oC Grand Junction. Thc tract contains <br />' approximately 20 acres. <br />Thc topo~aphy of lire tract is relatively Oat, formerly used as an irrigated farm field and pasture. Thc tract has <br />1 a ccn gentle slope to the southwest ~~~th an elevation of approximately 4530 to 4535 feet above sea level, using <br />the U.S G.S. 7- I/2 minute mapping of the Grand Junction Quadrangle. It is believed that minor amounts of <br />surface regrading has occurred in the past, probably associated with irrigation of the ground. Any previous sift <br />I regrading is bclicced to be vcq~ minor in extent, <br />Thc vact has been used for agricultural purposes. Thc tract has bcen subject to irrigation and is drained toward <br />the south southwest and eventually to the Colorado River via shallow drain ditches in the vicinih. Surface <br />drainage is fair to poor and the subsurface drainage is fair to good. <br />GENERAL GEOLOGY <br />Thc tract is located within the geologically active Oood plain of the Colorado River. This active Oood plain is <br />composed of approxiinatcly 25 to 30 feet of unconsolidated soils which are underlain by a very thick sequence <br />of sedimentary rocks. <br />The tract is underlain by the Mancos Shale Formation. The Maneos Shale is part of a thick sequence oC <br />' sedimentary rocks rehich gently dip or slope toward the north northwest. This dip in this general area ranges <br />from approximately 4 to 8 degrees from the horizontal. These sedimentary beds are dipping into the Piceancc <br />Basin structural fcauirc to the northeast. <br />Thts tract is located approximately 3 milts northeast of the steep slopes and cliffs of the Colorado National <br />Monument. Tlrc Colorado National Monument is at the northeast portion of the Uncompahgre UpIiA and the <br />' steep cliffs occrlooking the Redlands and Colorado River arc the surface expression of the Red]and Fault <br /> <br />