PERMFILE111851

• Permit No: C1982057A
• IBM Index Class Name: Permit File
• Doc Date: 5/1/2003
• Section_Exhibit Name: Tab 07 Hydrologic Description
• Media Type: D
• Archive: Yes

range from 404 to 660 mg/1, with an average of 507 mg/l. Overall, the Watering Trough •
Culch alluvium shows relatively stable water chemistry over time, although a small
increase in TDS, attributable to an increase in sulfate, is evident at GW-52W-BA1. r/e ry
little seasonal variability is app~rrent in th i:. aquifer; the largest variations occ ur• in
chloride ion concentrations which are approximately two times lower in the spring and
winter than in the summer and fall (Figure 7-1 ),
Water quality has been monitored at four walls (Gw-52W-6A2, -7A1, -7A2, and -~19A)
completed in the Hubberson Culch alluvium. Wa1:er chemistry monitoring at GW-5247-7A1 was
discontinued after 1982, and this well currently is only monitored for water levels.
Water chemistry is more variable in the Hubberson Gulch alluvium than the Watering Trough
Culch alluvium. Overall, the Hubberson Gulch alluvium has a mixed ion water type, but
water types at individual wells range from MgCa-504 to CaMgNa+K-HC03 (Table 7-12). This
variation appears to be controlled by location. Well CW-S2W-6A2, located on Hubberson
Gulch proper, has a CaMgNa+K-HC03 water type, while CW-52W-19A, which is located on a
tributary to Hubberson Gulch, has a MgCa-504 water type. Wells GW-52W-7A1 and -7A2 are
situated downstream from CW-52W-6A2 and -19A; the water chemistry at Wells GW-52W-7A1 and •
-7A2 is Ca-HC03SO4 and CaMg-HC03504, respectively, and these water types essentially are a
mix of the waters found at Wells CW-S2W-6A2 and -19A.
Field pH values for the Hubberson Gulch alluvium range from 6.70 to 8.10, with an average
of 7.30 (Table 7-13). Like the Watering Trough Gulch alluvium, the Hubberson Culch
alluvium contains water that is very hard, with an average hardness of 786.62 mg/1 of
CaC03. Also, the list of trace elements detected in this aquifer system are similar to
those found in the Watering Trough Gulch alluvium (Table 7-13). Most trace element
concentrations are less than 1.0 mg/1; exceptions are barium, manganese, and zinc values
of 2.2, 13.96, and 2.72 mg/7, respectively, all measured at GW-52W-7A1 on November 19,
' 1980, and an iron concentration of 61.00 mg/1 recorded at GW-52W-6A2 on October 19, 1981.
Total dissolved solids concentrations range from 454 to 2,416 mg/1, with an average of
1,066 mg/1. As stated above, water chemistry varies between sites within the Hubberson
Gulch aquifer, but water chemistry at individual wells is fairly consistent for the period
and TDS concentrations at Wells GW-52W-6A2 and
of record. Possible exceptions are S0
4
-7A2, which show a gradual increase with time, especially over the last three years.
There also is more evidence of seasonal variability in the Hubberson Gulch alluvium •
(Figure 7-2); all analytes show lower concentrations in the winter, and Mg, C1, 504, and
TDS concentrations are highest in the spring.
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