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Comparison of Surface Water Quality to Water Use Standards. SCC has <br />compiled a list of surface water standards for agricultural uses (Table <br />10). This list is composed of CDPHE surface water agricultural use <br />standards (CDPHE, Reg.31, November 2009). <br />Table 11 provides a comparison of all surface water quality data, <br />including the spoil spring, this year to agricultural standards. This <br />Paradox database generated table does not include the units of <br />concentration (mg /l or ug /1) for each parameter. The units used for each <br />parameter are the same as those listed on the standards table (Table 10) <br />and are also the same as those used in the water quality reports. The <br />frequency column on Table 11 indicates, in this order: uncensored, that <br />is, the number of exceedances above the Method Detection Limit (MDL) / <br />the number of exceedances between the MDL and the Practical Quantitation <br />Level (PQL) / censored, that is, the number of sample values below the <br />MDL but the MDL was higher than the standard / the total number of <br />samples. Below is a summary of standards that were exceeded. Given in <br />parenthesis is the source and use of each standard. Although the CDPHE <br />does not indicate between livestock and irrigation uses in their surface <br />water agricultural standards, they have done so in their similar ground <br />water agricultural standards (see Table 5). For the sake of discussion, <br />SCC chooses to use those ground water use standards classifications <br />(livestock or irrigation) for surface water use evaluation. <br />Parameter ## of Sites / ## of Excursions <br />Manganese (CDPHE irrigation) 2/4 <br />This summary indicates that only one CDPHE surface water agricultural <br />use standards were exceeded. The manganese standard was exceeded three <br />times at NPDESS and once at SSSPG9. However, as indicated in the <br />recently revised CDPHE Regulation 31, the standard of 0.2 mg /1, applies <br />to plants grown in acidic ( <6.0 pH) soils. In alkaline soils, as are <br />found in the Seneca II region, a more appropriate (EPA) standard would <br />be 10 mg /1. The maximum manganese value observed this year at any <br />surface water site was 1.63 mg /1. <br />