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decreasing at NPDES Ponds 009, 015 and 016 and Spoil Spring 5. The TDS <br />trend is stable at NPDES Ponds 005 and 017 and surface water Site WSSF3. <br />NPDES discharges are normally suitable for livestock and irrigation, but <br />sometimes exceed water quality standards for aquatic life. <br />In the Probable Hydrological Consequences (PHC, Tab 17, Table 17-42b) <br />section of the Seneca II-W Mine PAP, predictions were made as to the <br />expected TDS increases to be observed at various surface water sites. <br />The following table outlines these predictions along with this year's <br />observed average values (irrigation season, June-September). <br />Site Predicted TDS values (m /1) <br />WSHF1 2527 <br />WSD5 2451 <br />WSSF3 676 <br />* indicates value above prediction <br />This year's average TDS (m /1) <br />2060 <br />1870 <br />770* <br />Two surface water sites had TDS values below the PHC predictions. Only <br />one site, WSSF3 on Sage Creek, exceeded PHC predictions, and that was by <br />only 94 mg/l. However, the maximum June-September TDS value observed at <br />NPDES 015 and NPDES 009 (the only two Seneca II-W outfalls that <br />discharge to Sage Creek) was only 430 mg/l. It should be noted that the <br />PHC predictions were based data from 1982 to 1989, when Site WSSF3 had <br />an average flow of 1.18 cfs in June thru September. However, this year, <br />Site WSSF3 had an average flow of only 0.69 cfs in July. Since there was <br />less dilution water, TDS values were higher than predicted this year. <br />References <br />• <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 />Buchanan and Sumers. 1968. "Stage Measurements at Gaging Stations" <br />23