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Evaluation of Potential Well Impacts From <br />The Proposed Nix Property Sand and Gravel Operation <br />The Nix property is relatively flat and located in the historic floodplain of the St. Vrain River <br />approximately eight miles south of its confluence with the South Platte River. According to the <br />"Geologic Map of the Boulder, Fort Collins, Greeley Area" (USGS 1978), the Nix property is <br />underlain by Piney Creek alluvium, Broadway alluvium and aeolian deposits. The Piney Creek <br />and Broadway alluviums aze described as sandy and gravelly deposits azound 20 to 35 feet thick, <br />respectively. <br />The 1972 USGS open file report (Harr, et al) entitled "Hydrogeologic Chazacteristics of the <br />Valley-Fill Aquifer in the Brighton Reach of the South Platte River, Colorado" identifies the <br />depth of alluvium in this area as approximately 40 to 50 feet with a saturated thickness of 35 to <br />45 feet. Based on this report, groundwater across the Nix property flows in a northwesterly <br />direction towards St. Vrain Creek with a gradient of between 0.5 and 1 percent. The <br />transmissivity of the aquifer in this area is described in this same report as approximately <br />200,000 gallons per day per foot {gpd/ft). <br />3.0 DATA REVIEW AND COLLECTION <br />This evaluation was conducted from a review and analysis of existing data in the project area as <br />well as data obtained specifically for the study. Existing documents reviewed included: <br />• "Geological Map of the Boulder-Fort Collins-Greeley Area, Colorado" (USGS 1978) <br />• "Hydrogeologic Characteristics of the Valley-Fill Aquifer in the Brighton Reach of the South <br />Platte River Valley, Colorado" (USGS 1972) <br />• Proposed mine plan documents including "Extraction Plan Map," "Reclamation Plan Map," <br />"Drill Hole Location Map" and "Water Features, Well Owners Within One-Half Mile," <br />prepared by Banks and Gesso, L.L.C. for Owens Brothers Concrete <br />• Well permit records from the State Engineer's Office (SEO) for wells within one-half mile of <br />the proposed operation <br />011-074.000 Wright Water Engineers, Inc. Page 2 <br />November 2001 <br />