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<br />CNAPTERTHREE
<br />increases and the water quality deteriorates as the Dissolution Surface is approached (Welder and
<br />Sauhrier 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 1,411 feet, close
<br />to the base of the Leached Zone and just above the Dissolution Surface) had a TD n
<br />of 26,600 mg/l (Steigers 1997a, Steigers 1997b). Groundwater collected from grab sample at
<br />approximately 1,404 feet bgs neaz the Dissolution Surface during initial drilling o
<br />a TDS concentration of 61,600 mg/I.
<br />During drilling and subsequent sampling of American Soda's monitoring we1120-1,
<br />concentrations of chloride (1,047 to 27,400 mg/I), fluoride (5 t ,sulfate (280 to 290
<br />mg/1), nitrate (25 mg/1), nitrite (25 mg/1), bariu , c 6mitmt (0. to 1.342 mg/1),
<br />iron (0 4 to 9 8 mg/1) lead (0 055 to 0 7'Zmg/I) manganese (0 058 to 0 138,m )zinc (7 99~
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<br />to 8.568 mg/l), and pH (8.9) exceeded olorado groundwater standazds. +1 ~,,,..
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<br />The top of the Saline Zone forms the base of the Lower qur er. a Saline Zone has very low 1,,..1 <z
<br />permeability and very little recoverable groundwater. This zone is known for its high resistivity. w~ ~~ y
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<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 corridor, much of which pazallels existing pipeline rights-of--way. The pipelines
<br />would traverse a variety of surficial geologic materials including alluvium, co(luvium, 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 Parachute Creek are lazgely derived
<br />from the Green River and Uinta fomtations, 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 Parachute 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 Parachute Creek watershed
<br />~f 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 aze sulfate and
<br />bicarbonate. TDS concentrations range from 366 to 7,033 mg/1(COE 1985).
<br />. i
<br />Groundwater 3-21.
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