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Salt concentrations are measured by both electrical conductivity (EC) and <br />total dissolved solids (TDS) (TABLES Band 9). In natural, undisturbed <br />drainages, salt concentrations have an inverse relationship with flow; as flow <br />increases salt levels decrease and vice-versa. <br />In small drainages disturbed by mining; TDS levels increase downstream (Table <br />8). Additionally, in areas in which spoils aquifers have matured, TDS levels <br />in adjacent surface waters may be substantially influenced by peak spoils <br />discharge. TDS levels from backfilled spoils surrounding the Foidel Creek <br />underground mine range from 2500 mg/1 to 4200 mg/1 and large quantities of <br />this water can rapidly deteriorate adjacent surface waters when adequate <br />dilution is unavailable. As the time lag between peak surface runoff and peak <br />spoils discharge is several weeks, the surface waters surrounding the mine are <br />most vulnerable to high salt concentrations in the period immediately <br />following peak discharge, as well as during low flow periods in later summer. <br />Table 10: SUMMARY OF FISH CREEK MAY, 1986, SPRING AND SEEP SURVEY (MAY, 1986} <br />SOURCE No of Springs Percent of Volume of Percent of <br /> Total Springs Discharge Total Flow <br /> (%) (gpm) (%) <br />Twentymile Sandstone 7 31.8 81 25.5 <br />Lewis Shale 6 27.3 139 43.7 <br />Coal Seam 1 4.5 14 4.4 <br />Reclaimed Areas of 2 9.0 27 8.4 <br />Mine 2 <br />Other (Unidentified) 6 27.3 55-59 17.9 <br />Discharge of ground-water occurs at multiple sites within the permit boundary <br />of Foidel Creek Mine. The applicant located springs and seeps adjacent to <br />Fish Creek and identified their source in May, 1986 (Table 60 and Map 36). <br />Twenty-two seeps were recorded, of which most were derived from the Twentymile <br />Sandstone. The largest volumes were recorded from the Lewis Shale. The flows <br />which were observed in May represented 1.3% of the surface water flow observed <br />at site 1002 on Fish Creek during that period. <br />There is no doubt that spoils springs will come to predominate spring flow in <br />areas where surface mining has occurred. One 1300 acre block in Eckman Park <br />has two large springs which each have flows ranging from 50 gpm to 1200 gpm. <br />A 1450 acre area in western Eckman Park has at least nine large springs with <br />flows ranging from less than 1 gpm to 250 gpm. <br />Water extracted from the Yampa River downstream from its confluence with Trout <br />Creek is used for agricultural, industrial, municipal, domestic and stock <br />purposes. Irrigation ditches, within the Foidel Creek life of mine permit <br />-39- <br />