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. 2.05.6(3) <br />The primary potential sources of detrimental effects on <br />water quality caused by the prior mining pperation were: <br />Increase erosion from land disturbances in the mine- <br />site area; and <br />Increases in oil and grease from increased use of <br />machinery and trucks in the vicinity. <br />Evidence of increased erosion causing greater sediment loads <br />and turbidity in Hubbard Creek was nonexistent during the mining <br />operation. Hubbard Creek normally turns quite turbid after showers, <br />especially after heavy rains in its headwater area, and it is probable <br />that increased sedimentation from the mine would not be significant <br />if it occurred. Greater impacts would be from highly localized <br />showers that caused turbid runoff into an otherwise relatively clear <br />stream. <br />During the mining operation there was no evidence that the <br />operation either increased the turbidity or oil and grease content in <br />Hubbard Creek. The sedimentation ponds constructed to control run-off <br />from the mine worked effectively and there have been no discharges <br />from the reclaimed mine site, during the prior five year permit term, <br />from a local high intensity rainfall event. <br />Water quality data from Hubbard Creek did not indicate there <br />would be water quality problems from trace metals or other potentially <br />deleterious substances. The results of a one-year monitoring program <br />(1980) by U.S. Steel Corporation tend to confirm this. Samples were <br />taken from Hubbard Creek above Blue Ribbon (Station H-2; see pages 44 <br />and 44i) and below U.S. Steel's Hubbard Creek fan (Station H-1). <br />Thus, changes in water quality due to both disturbed areas, as well <br />as approximately one mile of country road, are included in this data. <br />Flow did not change. Acidity decreased 13.38, while alkalinity <br />increased 11.5 percent <br />• 123 (Rev. 12-16-92) <br />