REP07148

• Permit No: C1981071
• IBM Index Class Name: Report
• Doc Date: 4/1/1997
• Doc Name: 1996 ANNUAL HYDROLOGY REPORT
• Annual Report Year: 1996
• Permit Index Doc Type: HYDROLOGY REPORT
• Media Type: D
• Archive: No

Permit C-81-071 1996 Annual Hydrology Report
of 1995 were sustained throughout 1996. Lastly, TDS values beyond the previously
' established maximum were recorded in November, March, and August (Table 12). All values
for well 006-AW-2 during 1996 occurred within previously established ranges (Table 13).
SPOILS
Five wells (001-SP-6, 001-SP-7, 026-SP-1, 026-SP-2, and 026-SP-3) are monitored in the
spoils on a quarterly basis for water levels and field parameters. They are located at Mine 1
and Eckman Park and were installed in 1985 and 1986. Three of these wells (026-SP-1, 026-
SP-2, and 026-SP-3) require semi-annual water quality sampling as well. Sampling
requirements were completed at these wells during 1996 with the exception that the second
required water quality samples were not obtained until November, 1996. ~-~-a r,.,b/,~,...
The plots of the historic water levels in the spoil wells are presented on Figures 24, 26, 28, 30,
and 31. The water levels normally have a similar pattern to the alluvial wells: they respond
rapidly to the spring runoff and then decline rapidly in the summer. Wells 026-SP-1 and 026-
SP-3 have on occasion been dry by the fall, although this has not happened since 1988. Water
levels in these wells closely mirror the pattern of the spoil spring discharges discussed
elsewhere in the report. Wells 001-SP-6 and 001-SP-7 reflect fluctuation in the spoil aquifer
water table attributable to pumping activities associated with the adjacent Foidel Creek Mine.
Water quality data for wells 026-SP-1, 2, and 3 are summarized in Tables 14, 15, and 16 for the
1996 water year. Tables 14a through 16a provide period of record statistical summaries of
collected water quality data at each site. Figures 25, 27, and 29 provide graphical
representations of TDS concentrations recorded at each site. TDS values in wells 026-SP-1
• and 2 were observed to be elevated in the spring during the period of significant recharge to the
spoils aquifer. TDS levels were then observed to drop off later in the year. The opposite
pattern was evident at well 026-SP-3 with TDS levels observed to increase during the latter part
of the year and decrease during the spring runoff period.
Monitored water quality parameters at these wells during 1996 returned values within previously
established ranges with the following exceptions. Anew maximum field conductivity was
recorded in April at well 026-SP-1 along with new maximum TDS, SAR, and nitrate as N values.
Well 026-SP-2 returned a new maximum value for pH in November of 1995. Subsequent
measurements returned to typical levels. New maximum values for field and lab conductivity,
TDS, and nitrate as N were recorded in April. Anew maximum value for dissolved selenium
comprises the only atypical value returned for well 026-SP-3 during 1996. This value was
reported for April and is only 1 ug/I higher than the previous maximum.
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
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