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level test values this year were less than the MDL. All low level tests <br />were below the 0.01 ug/l stream standards. <br />NPDES Effluent Criteria (Permit No. CO-0000221). One excursion of NPDES <br />effluent limits occurred this year. See above discussion for the total <br />recoverable iron excursion experienced at NPDES8 in February. This <br />excursion should not be considered a NPDES violation, as CDPHE Reg. 31, <br />Footnote 4 to Table 3 states: "Both acute and chronic numbers adopted as <br />steam standards are levels not to be exceeded more than once every three <br />years on the average". <br />Surface Water Summary. Water discharged from the Seneca II Mine is not <br />used directly for irrigation. Indirectly, although, water discharged <br />from the mine is significantly diluted by water from Fish Creek before <br />it is diverted and used for irrigation. Due to the relative amount of <br />dilution by additional water from both sources, the ambient water <br />quality of Fish Creek is the dominant factor in determining their <br />suitability for irrigation. Water discharged from the Seneca II Mine is, <br />however, used for livestock watering. <br />TDS values at NPDES8 are increasing slightly. Spoil Spring 9 exhibits a <br />stable TDS trend. NPDES discharges are normally suitable for livestock <br />and irrigation, and rarely exceed water quality standards for aquatic <br />life. <br />A 76 mg/l increase in TDS was predicted by the PHC for Fish Creek in <br />June, while a 20 mg/1 increase was observed at Site SSF13. The winter <br />snowpack (as estimated from data at the NDCD's Hayden Station) for this <br />year was below average, and so was the annual average flow at NPDES8. <br />References <br />American Public Health Association (Ed.). 1985. "Standard Methods for <br />the Examination of Water and Wastewater", 16th Edition, Washington, D.C. <br />Brakensieh and others. 1979. "Field Manual for Research in Agricultural <br />Hydrology". <br />12