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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 />11) . This list is composed of CDPHE surface water agricultural use <br />standards (CDPHE, Reg.31, November 2009). <br />Table 12 provides a comparison of surface water quality (including <br />springs) to agricultural standards. This Paradox database generated <br />table does not include the units of concentration (mg /l or ug /1) for <br />each parameter. The units used for each parameter are the same as those <br />listed on the standards table (Table 11) and are also the same as those <br />used in the water quality reports. The frequency column on Table 12 <br />indicates, in this order: uncensored, that is, the number of exceedances <br />above the Method Detection Limit (MDL) / the number of exceedances <br />between the MDL and the Practical Quantitation Level (PQL) / censored, <br />that is, the number of sample values below the MDL but the MDL was <br />higher than the standard / the total number of samples. Below is a <br />summary of standards that were exceeded. Given in parenthesis is the <br />source and use of each standard. Although the CDPHE does not indicate <br />between livestock and irrigation uses in their surface water <br />agricultural standards, they have done so in their similar ground water <br />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. Following is <br />a list of standards exceeded this year. <br />Parameter # of Sites / # of Excursions <br />Manganese (CDPHE irrigation) 6/9 <br />Selenium (CDPHE irrigation) 1/1 <br />This summary indicates that two CDPHE surface water agricultural use <br />standard were 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 0.891 mg /1. <br />11 <br />