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indicates, in this order: uncensored, that is, the number of exceedances <br />above the Method Detection Limit (MDL) / the number of exceedances <br />between the MDL and the Practical Quantitation Level (PQL) / censored, <br />that is, the number of sample values below the MDL but the MDL was <br />higher than the standard / the total number of samples. Below is a <br />summary of standards that were exceeded. Given in parenthesis is the <br />source and use of each standard. Although the CDPHE does not indicate <br />between livestock and irrigation uses in their surface water <br />agricultural standards, they have done so in their similar ground water <br />agricultural standards (see Table 5). For the sake of discussion, SCC <br />chooses to use those ground water use standards classifications <br />(livestock or irrigation) for surface water use evaluation. Following is <br />a list of standards exceeded this year. <br />Parameter <br />Manganese (CDPHE irrigation) <br />Selenium <br /># of Sites / # of Excursions <br />5/9 <br />2/2 <br />This summary indicates that two CDPHE surface water agricultural use <br />standards were exceeded. The manganese standard was exceeded at five <br />sites and the selenium standard was exceeded at two sites. However, as <br />indicated in the recently revised CDPHE Regulation 31, the standard of <br />0.2 mg/1 for manganese, applies to plants grown in acidic (<6.0 pH) <br />soils. In alkaline soils, as are found in the Seneca II region, a more <br />appropriate (EPA) standard would be 10 mg/l. The maximum manganese value <br />for any surface water site observed this year was 0.680 mg/l. Premining <br />manganese values often exceeded the 0.2 mg/l standard. Three sites <br />exceeded the agricultural selenium standard. These exceedances will be <br />discussed below. <br />Table 13 shows the CDPHE receiving stream standards for Sage Creek <br />(Yampa Segment 13e), Table 15 shows the upper Grassy Creek (Yampa <br />Segment 13i) and Table 17 shows the lower Grassy Creek (Yampa Segment <br />13j). Sage Creek was re -segmented by the CDPHE in 2003. Regulation 33 <br />was further revised in 2005, 2008 and 2015. These standards were based <br />on the presence of fish in the lower portions of the creeks. However, <br />13 <br />