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. and have a relatively low permeability. Subsurface investigations <br />indicate that the Evacuation Creek member is unimportant as an <br />aquifer and will yield less than 10 gpm to wells in most places <br />within the site (Metcalf S Eddy, 1975). <br />GROUND WATER QUALITY <br />Samples of groundwater were collected from test holes, springs, <br />and seeps, then tested for water quality. Table G-9 lists the <br />test holes and wells. The water analyses were evaluated with <br />respect to site location and seasonal fluctuation. A summary <br />of the results indicate the following: <br />1) Available data indicate groundwater has not been contaminated <br />by man. <br />2) In general, the groundwater becomes more mineralized as <br />it moves southward across the property and as it moves <br />• deeper into the bedrock. <br />3) Recharge from spring snowmelt dilutes mineralization of <br />the groundwater in most cases. <br />4) The only potable groundwater was found in the alluvium <br />of Upper Davis Gulch and Upper Middle Fork Valley. <br />5) Water apparently suitable Eor processing and construction <br />is available from regional bedrock fractures underlying <br />Davis Gulch and Upper Middle Fork Valley. <br />6) Groundwater in other areas of the site is too highly minera- <br />lized for general use without some form of treatment (Metcalf <br />& Eddy, 1975). <br />Groundwater (precipitated water) initially has an insignificant <br />mineral content and exhibits a pH of about 6. As the water <br />travels down gradient and southward at the site, it interacts <br />with the geologic formations both alluvial and bedrock, becoming <br />more highly mineralized and alkaline (pH of about 7). This <br />movement results in increases of total dissolved solids, hardness, <br />• <br />G-23 <br />