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the water quality reports. The frequency column on Table 12 indicates, in <br />this order: uncensored, that is, the number of exceedances above the <br />Method Detection Limit (MDL) / the number of exceedances between the MDL <br />and the Practical Quantitation Level (PQL) / censored, that is, the number <br />of sample values below the MDL but the MDL was higher than the standard <br />/ the total number of samples. Below is a summary of standards that were <br />exceeded. Given in parenthesis is the source and use of each standard. <br />Although the CDPHE does not indicate between livestock and irrigation <br />uses in their surface water agricultural standards, they have done so in <br />their similar ground water agricultural standards (see Table 5). For the <br />sake of discussion, SCC chooses to use those ground water use standards <br />classifications (livestock or irrigation) for surface water use <br />evaluation. Following is a list of standards exceeded this year. <br />Parameter <br /># of Sites / # of Excursions <br />Manganese (CDPHE irrigation) 1/1 <br />Manganese, Pot. Dissolved 5/5 <br />This summary indicates that the sole CDPHE surface water agricultural use <br />standard exceeded was manganese. The manganese standard was exceeded at <br />six sites. However, as indicated in the recently revised CDPHE Regulation <br />31, the standard of 0.2 mg/l for manganese, applies to plants grown in <br />acidic (<6.0 pH) soils. In alkaline soils, as are found in the Seneca II <br />region, a more appropriate (EPA) standard would be 10 mg/l. The maximum <br />manganese value for any surface water site observed this year was 0.98 <br />mg/l. Premining manganese values often exceeded the 0.2 mg/1 standard. <br />Table 13 shows the CDPHE receiving stream standards for Sage Creek (Yampa <br />Segment 13e), Table 15 shows the upper Grassy Creek (Yampa Segment 13i) <br />and Table 17 shows the lower Grassy Creek (Yampa Segment 13j). Sage Creek <br />was re -segmented by the CDPHE in 2003. Regulation 33 was further revised <br />in 2005, 2008 and 2015. These standards were based on the presence of <br />fish in the lower portions of the creeks. However, the upper portions <br />that the Yoast Mine discharges into have no fish present. Tables 14 (Yampa <br />Segment 13e) 16 (Yampa Segment 13i) and 18 (Yampa Segment 13j) provide a <br />comparison of those standards to water quality data collected this year <br />13 <br />