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summary of standards that were exceeded. Given in parenthesis is the <br />source and use of each standard. Although the CDPHE does not <br />differentiate between livestock and irrigation uses in their surface <br />water agricultural standards, they have done so in their similar ground <br />water agricultural standards (see Table 5). For the sake of discussion, <br />SCC chooses to use those ground water use standards classifications <br />(livestock or irrigation) for surface water use evaluation. Of all the <br />surface water sites downstream of Seneca II -W, only Sites WSDS (Dry <br />Creek), WSSF3 (Sage Creek), WSH7 (mid-Hubberson Gulch) and WSHF1 (lower <br />Hubberson Gulch) have their waters used for irrigation. Following is a <br />list of standards exceeded this year. <br />Parameter # of Sites / # of Excursions <br />Manganese (CDPHE irrigation) 6/7 <br />This summary indicates that the only CDPHE surface water agricultural <br />use standard exceeded was manganese. The manganese standard was exceeded <br />at six sites. However, as indicated in the recently revised CDPHE <br />Regulation 31, the standard of 0.2 mg/l, applies to plants grown in <br />acidic (<6.0 pH) soils. In alkaline soils, as are found in the Seneca <br />II -W region, a more appropriate (EPA) standard would be 10 mg/l. The <br />maximum manganese value for any surface water site observed this year <br />was 1.06 mg/l at site WSPG50. Pre -mining manganese values often exceeded <br />the 0.2 mg/l standard. <br />Table 12 shows the CDPHE receiving stream standards for upper Dry Creek <br />(Yampa Segment 13d) and Table 14 shows the Sage Creek (Yampa Segment <br />13e). Sage Creek was resegmented by the CDPHE in 2003. Regulation 33 was <br />further revised in 2005, 2008 and 2015. These standards were based on <br />the presence of fish in the lower portions of the creeks. However, the <br />upper portions that Seneca II -W discharges into have no fish present. <br />Tables 13 (Yampa Segment 13d) and 15 (Yampa Segment 13e) provide a <br />comparison of those standards to water quality data collected this year <br />from NPDES and stream sites in those basins. Standards that were <br />exceeded are: <br />23 <br />