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hydrogsaph shore typical saasoml vaziation due to snorpack rvnof! in the spring. The <br />peak floc this yaaz ras the highart on record. Its TD9 plot indicatoe a decreasing trend. <br />NPDe3 006 (NPD8S6). This Bits is located on s tributary to Bubbarson n,i ch refereed to as <br />the 006 n.i cti. Comtruction o! the 006 Pond ras completed October 1989. This pond <br />collects all mine die^*•~s from the south ~ , azaa. The first hydrograph supplied <br />shore data for this yaaz; the second shore all data collected since the sits began <br />dischazginq. Revier of the floc hydrographs indicates typical seasonal vaziation due to <br />enormelt runof! in the spring, rith additional peaks due to pit pumpaga and ras.nlall <br />awnta. The rater yaaz average flora (from raekly meaeuremeata) since this pond began to <br />dischazge aze: <br />1997 0.303 cfe <br />1996 0.14 c!s <br />1995 0.106 cfe <br />199a 0.010 efs <br />1993 0.127 cfe <br />1992 0.036 cfe <br />1991 0.062 cfe <br />1990 0.055 cfe (pond did not completely till until lfarcti 29, 1990). <br />The above table indicates highest average flox on record. Floc values for this pond haw <br />been affected by s 3.d loot increase in epillray elawtion on July 31, 1991, the <br />installation of a 4-inch orifice on the riser pipe on November 2, 1995, and the dredging <br />of this pond that occurred during July and Auquet 1996. Aavier of the TD9 plot indicates <br />an increasing trend due to runoff from mine spoils. <br />From September 13 to the 22, 1997, <.36 inU~es of rain were masurad at Sanaca II-N. This <br />wlue is 2t percent of the average annml total observed base since 1990. This rainfall <br />event caused the NPD85 006 Pond to be completely tilled with sediment and also carved the <br />trash rack at the principle epillxay culvert to become clogged. m a result of the <br />clogged trash rar)c, rater ras Qiecharged through the emergency spillray (sea the September <br />25 sample record in Appandu E). The trash rarJc ras unclogged on September 26, resulting <br />in the dischazge of wry turbid rates (5500 mg/1 0! suspended solids). ey September 30, <br />discharged rater had cleared up significantly (< 5 mq/1 of suspended solids). The clean <br />out of this pond rill be discussed in the Wert ABR. <br />1! ,, <br />u <br />• <br />8 <br />