2010-03-22_REPORT - C1982057 - Laserfiche WebLink

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Comparison of Ground Water Quality to Water Use Standards. SCC has compiled a list of ground water standards for agricultural uses (Table 5). This list is composed of Colorado Department of Health ground water standards (CDPHE, Reg. 41, May 2008). Table 6 provides a comparison of ground water quality to agricultural standards. This Paradox database generated table does not include the units of concentration (mg/l or ug/1) for each parameter. The units used for each parameter are the same as those listed on the standards table (Table 5) and are also the same as those used in the water quality reports. The frequency column on Table 6 indicates the number of exceedences out of the total number of samples (i.e., 1/2 indicates one exceedence out of two samples). Below is a summary of standards that were exceeded. Given in parenthesis is the source and use of each standard. Parameter is Boron (CDPHE, irrigation) pH (CDPHE, irrigation) Iron (CDPHE, irrigation) Manganese (CDPHE, irrigation) Selenium (CDPHE, irrigation) Zinc (CDPHE, irrigation) # of Wells # of Excursions 1/1 1/1 2/2 6/11 1/1 1/1 Elevated levels of iron may be attributed to natural (i.e., not mining related) conditions, since elevated levels for that parameter are not normally found in spoil wells at the adjacent Seneca II Mine. The two bedrock wells (WW14 and WTC201) that often exhibit high levels may have higher than usual concentrations of iron pyrite in the rock. Well WTC201 (Trout Creek Sandstone, shop well) often displays high iron values, but does not display an increasing trend. Wadge coal well WW14 started displaying high iron values in 1998, with a peak value occurring in 2001. High manganese values may, in part, be due to recharge from the spoil aquifer, although high values are often common, especially in alluvial 9