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• Monitored water quality parameters at these wells during 1997 returned values within previously established ranges. In general, the spoil groundwater has comparable dissolved solids concentrations to most of the spoil spring discharge, but much higher values than in the background bedrock ground water. Much of spoil ground water is acalcium-sulfate type with relatively high bicarbonate and low SAR. Spring 114, located just downgradient from wells 001-SP-6 and 001-SP-7, typically exhibits higher sodium and sulfate levels than other spoil springs. The water quality data for spoil wells does not indicate any significant changes in trace metals concentrations have occurred over time. SURFACE WATER MONITORING Foidel Creek: Four surface flow monitoring sites on Foidel Creek in the vicinity of the CYCC mined areas and facilities areas are utilized. Site 14 provides data from the undisturbed watershed area adjacent to (northeast of) Eckman Park. Site 800 is located a short distance downstream from Eckman Park below the confluence of the Pond A discharge and site 14 and flows at this station are monitored by the USGS (Station 09243800). Site 8 is located a short distance downstream of the Foidel Creek mine portal area below Mine 1. And lastly, site 900 is located further downstream above the confluence with Middle Creek. Flows at site 900 are also are monitored by the USGS (Station 09243900). During 1997, all four Foidel Creek surface water monitoring sites required monthly flow and field parameter measurements with quarterly water quality sample collection. The monitoring requirements are further described to require 12 flow and field parameter monitoring instances to occur between March and • September along with 4 water quality sampling events. One additional site on Foidel Creek, site 304, required water level monitoring on a monthly basis in conjunction with alluvial well 008-AV-2. All required monitoring instances were completed during 1997. Tables 18 through 22 provide summaries of the 1997 Water Year data collected at each site. Tables 18a through 21a provide period of record statistical summaries of collected data at specified sites. Table 22a provides a water level summary for site 304. Figures 32 through 47 provide graphical representations of flow rates and selected water quality parameters recorded at each site. Typical flow patterns were exhibited at these sites with spring runoff periods accounting for the peak flows observed. Runoff magnitudes were slightly higher than average during 1997 based upon comparison with previous years data. At all of these sites, the inverse relationship between flow and field conductivity continues to be evident, though not as pronounced as in previous years. Water quality parameter analyses conducted at these sites during the year returned values within previously established ranges with the exceptions of a new minimum sulfate figure reported at site 8 in September. The base level of field conductivity measured during the fall was higher in the downstream sites on Foidel Creek. It measured approximately 900 umhos/cm in the upstream site (14) and approximately 2800 umhos/cm in the downstream sites 8 and 800. Since approximately 1981, the base level for conductivity at both downstream sites has been increasing although there appears to have been a leveling off since approximately 1989. The upstream site also reflects a notable conductivity increase in 1986, but appears to be slowly declining. The difference between the conductivities at the upstream and downstream stations is attributable primarily to spoil spring discharges related to surface mining. These discharges • cause increased concentrations of dissolved solids, calcium, magnesium, and sulfate and a reduction in SAR in Foidel Creek. However, the increase in TDS levels during irrigation EP97TEXT.DOC 07/01/98 5