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•` site. Below the Trout Creek is a 400 ft.-thick shale sequence underlain <br />by about 1,000 ft. of massive sandstones interbedded with sand shale, <br />shale, and coal beds. The Iles conformably overlies the dark-gray marine <br />Mancos shale. <br />4.1.1.4 Groundwater Aquifer <br />The principal groundwater bearing zones in the Hayden Gulch area are the <br />coals and massive sandstones of the 4lilliams Fork and Iles formations. <br />Gr-oundwater moves northeast following the dip of the strata toward the <br />axis of the Watering Trough syncline. These zones are recharged at and <br />near their southwestern outcrops along canyon walls. Discharge takes <br />place at seeps and springs along the valley floors where the aquifers <br />outcrop. The aquifers appear to be nearly dry as their outcrops to the <br />south of the site are approached and contain increasingly more water to <br />the northeast. <br />4.1.1.5 Regional Seeps and Springs <br />• Springs and seeps were inventoried within a one mile radius of the site. <br />A total of 18 springs and seep areas were identified (Exhibit 1). Field <br />measurements of specific conductivity, pH, temperature, color, and flow <br />(where possible) were made for eight of the springs and seeps (Table 1), <br />and five water samples were collected for laboratory analysis (Table 2 <br />and Exhibit 4). Specific conductivity ranged from 940 to 1,320 umhos, pH <br />from 6.8 to 7.1, and total dissolved solids from 1,200 mg/1 to 1,510 mg/1. <br />The analyses indicated that the water from the various springs and seeps <br />is similar in quality. All samples were relatively high in calcium and <br />sulfate and relatively low in sodium, potassium, and chloride. NAS water <br />supply standards for iron, maganese, and sulfate were exceeded by springs <br />SP 2 and SP 4 (PJational Academy of Sciences and PJational Academy of Engi- <br />neering, 1972). NAS Sulfate standards were also exceeded by SP 1, SP 6, <br />and SP 14. <br />All but four of the springs and seeps draw water from water-bearing zones <br />well below the mining zone. The presence of massive impermeable shale <br />layers between the mining zone and these lower water-bearing zones (Twenty <br />7 <br /> <br />