Laserfiche WebLink
• <br />• <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 spoil springs) 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 <br />Cadmium (CDPHE irrigation) <br />Manganese (CDPHE irrigation) <br />Nickel (CDPHE irrigation) <br /># of Sites / # of Excursions <br />1/1 <br />11/23 <br />1/1 <br />This summary indicates that only three CDPHE surface water agricultural <br />use standards were exceeded. The manganese standard was exceeded at <br />eleven sites. However, as indicated in the recently revised CDPHE <br />Regulation 31, the standard of 0.2 mg/l, applies to plants grown in <br />acidic (<6.0 pH) soils. In alkaline soils, as are found in the PSCM <br />region, a more appropriate (EPA) standard would be 10 mg/1. The maximum <br />manganese value observed this year at any NPDES outfall was 0.836 mg/l <br />at NPDES3. All stream sites had manganese values less than 0.40 mg/1, <br />and all but one spoil springs were less than 10 mg/1. It should also be <br />17