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5). For the sake of discussion, SCC chooses to use those ground water <br />use standards classifications (livestock or irrigation) for surface <br />water use evaluation. Following is a list of standards exceeded this <br />year. <br />Parameter # of Sites / # of Excursions <br />Manganese (CDPHE irrigation) 7/9 <br />This summary indicates that only one CDPHE surface water agricultural <br />use standard was exceeded. The manganese standard was exceeded at six <br />sites. However, as indicated in the recently revised CDPHE Regulation <br />31, the standard of 0.2 mg/1, applies to plants grown in acidic (<6.0 <br />pH) soils. In alkaline soils, as are found in the Seneca II region, a <br />more appropriate (EPA) standard would be 10 mg/l. The maximum manganese <br />value for any surface water site observed this year was 1.32 mg/l. <br />Premining manganese values often exceeded the 0.2 mg/l standard. <br />Table 11 shows the CDPHE receiving stream standards for Sage and Grassy <br />Creeks (Yampa Segment 13e, Reg. 33, January 2009). These aquatic life <br />standards were based on the presence of fish in the lower portions of <br />the creeks. However, the upper portions that the Yoast Mine discharges <br />into have no fish present. Table 12 provides a comparison of those <br />standards to water quality data collected this year from NPDES and <br />stream sites in the Sage and Grassy Creek basins. Standards that were <br />exceeded are: <br />Parameter # of Sites / # of Excursions <br />Iron, Total Rec. 4/6 <br />Mercury 1/1 <br />Nitrite 1/1 <br />Selenium 1/2 <br />Sulfide 1/1 <br />The total recoverable iron standard (1.0 mg/1) was exceeded six times <br />this year. Excursions were normally related to high suspended solids. <br />The two NPDES site excursions occurred during snowmelt runoff in April <br />12