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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. <br /> <br />• <br />Parameter <br />Cadmium (CDPHE irrigation) <br />Nickel (CDPHE irrigation) <br />Manganese (CDPHE irrigation) <br /># of Sites / # of Excursions <br />1/1 <br />1/1 <br />10/16 <br />This summary indicates that only three CDPHE surface water agricultural <br />use standards were exceeded. The manganese standard was exceeded at ten <br />sites. However, as indicated in the recently revised CDPHE Regulation <br />31, the standard of 0.2 mg/l, 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/1. The maximum manganese <br />value observed this year at any NPDES outfall was 2.37 mg/l at NPDES8. <br />All stream sites had manganese values less than 0.73 mg/1, and all but <br />one spoil springs were less than 5 mg/1. It should also be noted that <br />the site on Grassy Creek (SSG1) that is upstream of Seneca II discharges <br />also experienced exceedences of the 0.2 mg/l standard. <br />Spoil Spring 6 exceeded the cadmium, nickel and manganese agricultural <br />standards. However, a same day sample collected downstream at Spoil <br />Spring 6A experienced none of these exceedances. <br />Table 13 shows the CDPHE receiving stream standards for Fish Creek <br />(Yampa Segment 13b). Table 14 provides a comparison of those standards <br />to water quality data collected this year from NPDES and stream sites in <br />the Fish Creek basin. The stream standards for Fish Creek are based on <br />aquatic life standards, even though there are no fish present in the two <br />tributaries that NPDES4 and NPDES8 discharge into. Standards that were <br />exceeded are: <br />Parameter <br />Iron, Total Rec. <br />of Sites / # of Excursions <br />2/6 <br />19