Laserfiche WebLink
soils. In alkaline soils, as are found in the Seneca II-W region, a more <br />appropriate (EPA) standard would be 10 mg/1. The maximum manganese value <br />for any surface water site obse rved this year was 1.85 mg/1 at Spoil <br />Spring 3. Premining manganese values often exceeded the 0.2 mg/1 <br />standard. <br />Table 11 shows the CDOH receiving stream standards for Dry Creek (Yampa <br />Segment 13 d) and Sage Creek (Yampa Segment 13 e). Sage Creek was <br />resegmented by the CDOH in 2003. Regulation 33 was further revised in <br />December 2005. These standards were based on the presence of fish in <br />the lower portions of the creeks. However, the upper portions that <br />Seneca II-W discharges into have no fish present. All standards for 13d <br />and 13e are the same except for selenium (see Table 11). Table 12 <br />provides a comparison of those standards to water quality data collected <br />this year from NPDES and stream sites in those basins. Standards that <br />were exceeded are: <br />Parameter # of Sites / # of Excursions <br />Iron, Total Rec. 6/10 <br />Sulfide 6/7 <br />Only one of the ten iron exceedances was from a NPDES site. It was due <br />to a high suspended solids value, 36 mg/1 at Pond 017. This strict <br />aquatic life standard (1.0 mg/1) was exceeded in over half of the <br />premining stream samples. <br />Seven samples experienced exceedances of the sulfide standard (0.002 <br />mg/1 un-ionized) this year. Four of these exceedances were from NPDES <br />sites. All exceedances were associated with high suspended solids. The <br />analytical method available to SCC detects both dissolved sulfides and <br />acid-soluble metallic sulfides present in suspended matter. It is <br />suspected that a large portion of the sulfides detected is of the latter <br />type, which would bias the un-ionized results high. Any dissolved <br />sulfides present in surface water should eventually oxidize to sulfates. <br /> <br />22 <br />