Laserfiche WebLink
Table 10 provides a comparison of surface water quality to agricultural <br />standards. This Paradox database generated table does not include the <br />units of concentration (mg/1 or ug/1) for each parameter. The units used <br />for each parameter are the same as those listed on the standards table <br />(Table 9) and are also the same as those used in the water quality <br />reports. The frequency column on Table 10 indicates the number of <br />exceedences out of the total number of samples (i.e., 1/2 indicates one <br />exceedence out of two samples). Below is a summary of standards that <br />were exceeded. Given in parenthesis is the source and use of each <br />standard. Although the CDPHE does not indicate between livestock and <br />irrigation uses in their surface water agricultural standards, they have <br />done so in their similar ground water agricultural standards (see Table <br />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/1. The maximum manganese <br />value for any surface water site observed this year was 0.731 mg/1. <br />Premining manganese values often exceeded the 0.2 mg/1 standard. <br />Table 11 shows the CDPHE receiving stream standards for Sage and Grassy <br />Creeks (Yampa Segment 13e, Reg. 33, December 2005). These standards were <br />based on the presence of fish in the lower portions of the creeks. <br />However, the upper portions that the Yoast Mine discharges into have no <br />fish present. Table 12 provides a comparison of those standards to water <br />quality data collected this year from NPDES and stream sites in the Sage <br />and Grassy Creek basins. Standards that were exceeded are: <br />12 <br />