2013-12-17_PERMIT FILE - C1992081 ‎(18)‎

• Permit No: C1992081
• IBM Index Class Name: Permit File
• Doc Date: 12/17/2013
• Section_Exhibit Name: Tab 07 Hydrologic Description
• Media Type: D
• Archive: No

• Although the xatar levels at xells HGOALS and HGDAL2 ahox little seasonality, same of the
chemical parameters do. At xell H®AL1, bicarbonate (HCO3) , calcium (Ca) , and 30, values
generally increased slightly £rom spring to £all. Prior to 1993, total concentrations of B
and Dot and Ammonium (Ntt~) generally ahoxad concentration increases from spring to fall xhila
Mg generally displayed a two to three factor increase; nitrate (N03) and total Se levels
generally declined from spring to fall. Since 1993, trace metal diaeolved concentrations,
with the exception of Fe and Mn xere generally near the loxer detection limit.
In samples collected prior to 1993 from wall H(~AL2, total B concentrations generally
increased by a factor of two to four from spring to fall, while HCOa generally increased by
a Factor of two to three, Ca concentrations generally increased by a Pactor o£ two, and
total Nn generally by a Factor o£ three betxean spring and fall. Ng, Na, and 30. levels
ahox increases of up to a factor of 10 from spring to fall. NEi~ concentrations ahox slight
increases while NOS values ahox alight deereases from spring to fall. From 1993 through
1995, Na and diaeolved Mn appear to ba the only constituents which display seasonality, with
slight concentration increases from spring to fall.
At well HGDAL3, seasonality trends era generally not apparent with the exception of Ca which .
ahoxa a alight decrease in concentration From spring to Fall and H, Mn, and NO3 which
display an increase in concentration values from spring to fall.
A comparison of ground rater data collected from June 1994 through October 1995 at wells
• HGDALl, AGDAL2, and HGDAL3 ie presented in Table 7-4. TD9, 90., Na, and chloride (Cl)
levels generally ahox a prograesiva drop from upgradiant roll HGDALI to do.mgradient well
HGOAL3. Tha high concentrations of Na and C1 at wells HGDALI and HGDAL2 strongly suggest
these portions of the Dry Creak alluvium are being in£luanced by upgradient irrigation
return Flow and dryland farming/Lexis shale seepage. Hecauae o£ the concern with where
wells HGDALI and HGDAL2 were completed, and the similarity of water quality betxean HGDAL2
and HGDAL3, monitoring at walls HGDALI and HGDAL2 ceased following the October 1995 sampling
avant. Since October 1995, ground water sampling has only occurred at well HGDAL3. The
ground water data indicate that there are no long-term increasing trands evident for any
chemical parameter monitored at the HGT monitoring wells.
Trilinear diagram plots for the three alluvial walls are shown on Figures 7-1 through 7-3
and Schoeller plots oP the major ions and TD9 era shorn on Figures 7-4 through 7-6. As H-G
Coal Company did not analyze Por potassium (R) and C1 concentrations, the concentrations of
K and Cl for all pre-1993 samples were estimated using IDaq/1 percentages determined From the
averaged Juno 1993 through October 1995 analyses which did include Rand C1 concentrations.
The cation points Por HGDALS and HGDAL2 ahox soma acattar; however, there is no trend to
the scatter. Tha Schoeller plot for H®AL1 indicates the June 15, 1990 Na value may be
erroneous and the 9choeller plot for HGDAL2 suggests the Nay 12, 1992 Na value and the
August 13, 1990 TDS value are erroneous. Cation points for wall HGDAI.3 dose not display any
scatter. Historically, well HGDALI

RM-o~
5 Revised 2/98