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I--1 <br />l _1 <br />i CHAPTERTHREE Affected Environment <br />increases and the water quality deteriorates as the Dissolution Surface is approached (Welder and <br />Saulnier 1978, Daub 1996). <br />Water quality data collected during the initial drilling of American Soda's solution mining well <br />20-3 indicate that water in the Lower Aquifer (from a grab sample collected at 1,41 l feet, close <br />to the base of the Leached Zone and just above the Dissolution Surface) had a TDS concentration <br />of 26,600 mg/1(Steigers 1997a, Steigers 1997b). Groundwater collected from a grab sample at <br />approximately 1,404 feet bgs near the Dissolution Surface during initial drilling of well 20-1 had <br />a TDS concentration of 61,600 mg/1. <br />' During drilling and subsequent sampling of American Soda's monitoring well 20-1, <br />concentrations of chloride (1,047 to 27,400 mg/1), fluoride (5 to 40.5 mg/1), sulfate (280 to 290 <br />mg/1), nitrate (25 mg/I), nitrite (25 mg/1), barium (1.69 mg/1), chromium (0.102 to 1.342 mg/1), <br />' iron (0.4 to 9.8 mg/1), lead (0.055 to 0.732 mg/1), manganese (0.058 to 0.138 mg/1), zinc (7.992 <br />to 8.568 mg/l), and pH (8.9) exceeded Colorado groundwater standazds. <br />r Saline Zone <br />The top of the Saline Zone forms the base of the Lower Aquifer. The Saline Zone has very low <br />' permeability and very little recoverable groundwater. This zone is known for its high resistivity. <br />3.4.2.2 Pipeline Corridor <br />The project pipelines (product and water return lines) would be routed along an approximately <br />44-mile-long comdor, much of which pazallels existing pipeline rights-of--way. The pipelines <br />would traverse a variety of surficial geologic materials including alluvium, colluvium, and <br />bedrock. The pipelines would be buried approximately three feet below grade. <br />Shallow groundwater in alluvial sediments would likely exist along this portion of the pipeline, <br />and the groundwater conditions described in Section 3.4.1 would likely exist. The upland areas <br />of the pipeline corridor aze underlain by the Upper and Lower Aquifers discussed in Section <br />3.4.1.1. <br />3.4.2.3 Parachute Site <br />' The sediments of the alluvial aquifer system associated with Pazachute Creek aze largely derived <br />from the Green River and Uinta formations, with some contribution to the streambed from the <br />Wasatch Formation (COE 1985). Groundwater levels in the alluvium of the East, Middle, and <br />West Forks Pazachute Creek have been observed to vary from 10 to 45 feet bgs (COE 1985). <br />Historic groundwater quality data were collected from wells in the Pazachute Creek watershed <br />from the mid-1970s to the eazly 1980s (COE 1985). These data indicate that the alluvial waters <br />are slightly alkaline, ranging in pH from 7.2 to 8.2. The major anions are sulfate and <br />bicazbonate, TDS concentrations range from 366 to 7,033 mg/1(COE 1985). <br />Groundwater 3-21 <br />