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• developed for each site. These values represent best estimates but are unsubstantiated with measured data. The only water quality parameter value noted to occur outside of previously established ranges was a new maximum lab pH at site 1002 in September (Table 25). At all sites, the inverse relationship between flow and field conductivity was generally evident. The dissolved solids concentrations in the upstream station of Fish Creek (16) are generally slightly lower than those in the downstream station (1002). There is also a slight downstream trend of increasing sodium and sulfate concentrations while calcium; magnesium and bicarbonate concentrations remain fairly consistent. The proportionally higher sodium concentrations over calcium and magnesium leads to a slight downstream increase in SAR. These major ion changes are more apparent during the low-flow period. The increase in TDS could be caused to some extent by evapotransporative effects, but this would not account for the major ion changes. These changes are more likely attributable to discharges of waters having higher sodium and sulfate concentrations than the Fish Creek water. One source of such discharge is the spoil runoff and springs associated with Mine 2. However, the very low flows associated with the Mine 2 disturbed areas indicates minimal influence from this source. The primary source of such water used to be the Foidel Creek mine underground mine discharge point located near Mine 2. During 1997 however, there was no discharge from that location. Trout Creek: Two surface flow monitoring sites on Trout Creek are utilized. Site 301 is located on Trout Creek above the confluence with Middle Creek and site 69 is located on Trout Creek below the confluence. Required monitoring for these sites included monthly flow, field • parameter, and water quality sampling during the inigation season June through September. Site visitation and water quality sampling requirements were met at these sites during 1997. Tables 28 and 29 provide summaries of the 1997 Water Year data collected at Trout Creek surface flow sites. Tables 28a and 29a provide period of record statistical summaries of collected data at sites 301 and 69. Period of record flow summaries for these sites are provided as Tables 28b and 29b. Figures 56 through 63 provide graphical representations of water levels and selected water quality parameters recorded at each site. For the most part, typical patterns were observed although flow magnitudes were higher than average. Again, peak flow estimates were derived from extrapolated flow curves in some instances. The single identified water quality variance includes a new maximum recorded for iron at site 69 in June. Since 1987, except for a short period during 1990, the salt content of Trout Creek below Middle Creek has been consistently higher than above Middle Creek. Typically, there is approximately 100 to 200 umhoslcm increase in field conductivity over this reach. The downstream increase was again apparent during the 1997 water year. This is probably due to the effects of Middle Creek flows that have a higher salt content than Trout Creek, primarily as a result of Foidel Creek which flows into Middle Creek just upgradient of the Trout Creek confluence. Foidel Creek salt loads during the spring runoff are primarily due to the impact of surface mine discharges. However, the Trout Creek salt content increase has not caused material damage, nor is there any increase in trace metal levels. SPOIL SPRING MONITORING A spoil spring monitoring program was initiated in 1986 and will be conducted annually until . such time as the monitoring requirement is eliminated. According to the approved plan, the annual mine-wide survey is conducted during May with springs measured for flow and field EP97TEXT.DOC 07/01/98 7