Laserfiche WebLink
• <br />Flow values for this pond have been affected by a 3.4 foot increase in <br />spillway elevation on July 31, 1991, the installation of a 4 inch <br />orifice on the riser pipe on November 2, 1995, and the dredging of this <br />pond that occurred in the summer of 1996 and the fall of 199'7. An <br />upstream presettling pond was added in March 1998. The principle <br />spillway elevation was changed again, and the dewatering orifice <br />removed, in August 1996. In August 2003, an 18-inch riser pipe was <br />installed on the discharge culvert, and the presettling pond was <br />removed. Additional dredging (and dewatering) occurred in the fall of <br />2004. Also affecting discharges from this pond are the pumping of water <br />from this pond for water trucks and the pumping of water into this pond <br />from the mine water supply well (WTC201). <br />Review of the TDS plot indicates an increasing trend due to runoff from <br />mine spoils. Baseline data for this site (WS H6) has been provided in <br />Appendix E1. <br /> <br />- Surface Water Site SW-S2W-FG1 (WSHF1). This site is located on <br />Hubberson Gulch downstream of the 006 Gulch confluence. It has been <br />monitored since July 1979. Irrigation ditches were established adjacent <br />this site in July 1999. The TDS plot indicates an increasing trend. The <br />peak TDS occurred in September 2002. Baseline water quality statistics <br />have been provided in Appendix E1. The Seneca II-W PHC, Table 17-42b, <br />predicts an irrigation season (June-September) average TDS value of 2527 <br />mg/1 for this site, while a value of 1930 mg/1 was observed this year. <br />- NPDES 005 (NPDESS) This sediment pond is located in the north mining <br />area on a tributary to Dry Creek referred to as the 005 Gulch. <br />Construction of this pond was completed in July 1992 and the First <br />discharge occurred on April 22, 1993. This pond was dredged in the <br />summers of 1998 and 2001. The water year average flows values since this <br />pond began to discharge are: <br />2006 0.038 cfs (monthly measurements) • <br />2005 0.021 cfs (monthly measurements) <br />16 <br />