2008-02-20_REPORT - C1980001

• Permit No: C1980001
• IBM Index Class Name: REPORT
• Doc Date: 2/20/2008
• Doc Name: 2007 Annual Hydrology Report
• From: WWC Engineering
• To: DRMS
• Annual Report Year: 2007
• Permit Index Doc Type: Hydrology Report
• Media Type: D
• Archive: No

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4 show an increase in several parameters directly after repair, some of which have begun to
stabilize and decrease to historical levels. Prior to 2003, parameters at the well had stabilized.
Therefore, it is assumed that this increase is due to the well repairs.
Monitoring of Well TCS-1 was initiated in 1995 to ensure the absence of mining
impacts on the Trout Creek Sandstone aquifer. Results of the monitoring efforts are provided
in Appendix F. To date, no impacts from mining activity are evident in Well TCS-1. TCS-1
was not sampled in 2004 due to equipment problems. The demolition of an adjacent house
removed power from the site. During demolition the well sustained damage. Sampling was
attempted using a generator but the well was deemed not functional. TCS-1 was refurbished
in the fall of 2005 and sampled thereafter. The 2007 sampling event constituent
concentrations were generally within historical water quality values for most constituents.
Chloride spiked in May of 2006.
Ground water sampling is performed in accordance with EPA approved methods and
instrumentation. The ground water quality at the Edna Mine is monitored via the parameters,
locations and frequency listed in Table 4.6-54, Section 4.6.8.4 of the permit. Analyses results
for monitoring wells TR-1.5, TR-3, TR-4, WR-1 and TCS-1 are found in Tables 8, 9, 10, 11
and 12. Results of the analyses are discussed below.
4.2.1 Ground Water Temperature
Chart 22 shows temperature values for monitoring wells TR-1.5, TR-3, TR-4, WR-1
and TCS-1 for the period of record. Temperature exhibited the same trends in 2007 as found
during baseline studies and previous years monitoring. Specifically, patterns in temperature
are seasonal, warming until July or August and than cooling throughout the remaining
sampling season. The amount of temperature fluctuation in Well TR-4 has been historically
somewhat greater than expected suggesting the flow to the perched aquifer, although
subsurface, is very shallow. The lowest temperature in 2007 was recorded at monitoring well
TR-3 in May with a reading of 6.8 °C and the high was recorded at monitoring site TR-4 in
July with a reading of 15.4 °C.
4.2.2 Ground Water pH
Chart 23 shows pH concentrations for monitoring wells TR-1.5, TR-3, TR-4, WR-1
and TCS-1 for the period of record. Values of pH during 2007 remained relatively constant
over the monitoring period. There is no apparent trend regarding pH although most wells,
except TCS-1, had a drop in August of the 2007 monitoring season. Overall, the groundwater
has tended to be alkaline throughout the period of record. The lowest pH value in 2007 was
recorded at monitoring well WR-1 in August with a reading of 6.81 standard units and the
high was recorded at monitoring well TCS-1 in October with a reading of 8.3 standard units.
4.2.3 Ground Water Specific Conductivity and Total Dissolved Solids
Charts 24 and 25 show specific conductivity and TDS concentrations for monitoring
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