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reports. The frequency column on Table 10 indicates the number of exceedences out of the total number of samples (i.e., 1/2 indicates one exceedence out of two samples). Below is a summary of standards that were exceeded. Given in parenthesis is the source and use of each standard. Although the CDOH does not indicate between livestock and irrigation uses in their surface water agricultural standards, they have done so in their similar ground water agricultural standards (see Table 5). For the sake of discussion, SCC chooses to use those ground water use standards classifications (livestock or irrigation) for surface water use evaluation. Of all the surface water sites downstream of Seneca II-W, only Sites WSDS (Dry Creek), WSSF3 (Sage Creek), WSH7 (mid- Hubberson Gulch) and WSHF1 {lower Hubberson Gulch) have their waters used for irrigation. Following is a list of standards exceeded this year. Parameter # of Sites / # of Excursions manganese (CDOH, SW, irrigation) 5/8 Review of this list indicates that only one CDOH surface water agricultural use standards was exceeded. The manganese standard was exceeded at five sites. However, as noted previously in the ground water discussion, the relatively low CDOH standard o£ 0.2 mg/1, according to the EPA, applies to plants grown in acidic soils. In alkaline soils, as are found in the Seneca II-W region, a more appropriate (EPA) standard would be 10 mg/1. The maximum manganese value for any surface water site observed this year was 1.22 mg/I. Premining manganese values often exceeded the 0.2 mg/1 standard. Table 11 shows the CDOH receiving stream standards for Sage and Dry Creeks (Yampa Segment 13d). Table 12 provides a comparison of those standards to water quality data collected this year from NPDES and stream sites in those basins. Standards that were exceeded (excluding ammonia and sulfide) are: r'1 LJ I 20