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. Williams Fork River flow data. The Williams Fork River gaging station (WF-2) is near the confluence with <br />the Yampa River, downstream of the Eagle No. 5 Mine discharge. The staff gage (WF-1) is located upstream <br />of the mine discharge points. Under TC, Williams Fork surface sampling (site WF-1) is measured for water <br />level and field parameters on an annual basis (between July 20th and August 30th), and requires an annual <br />water quality analysis (See Table 3). WF-2 is also monitored concurrent with WF-1. <br />The flow data for WF-2 was historically provided by the USGS, however, monitoring of the Williats Fork <br />stations was discontinued in 2001. Historically, comparisons between up gradient site WF-1, and down <br />gradient site WF-2, have not show any stream depletion impacts from mine dewatering. In 2005 the Stale <br />Division of Water Resources reactivated the site. A preliminary copy of their data is provided at the back of <br />this AHR under Support Data. <br />Summaries of WF-1 and WF-2 water quality data are presented in Tables 13 through 16. A plot of upstream <br />and downstream dissolved solids measurements for the river is presented in Figure 8. The data indicates that <br />the surface water quality does not show any significant variation from expected values. The comparisons of <br />data from the upstream and downstream station on the Williams Fork River indicate that there is no detectable <br />effect of mining on river water quality. As expected, dissolved solids decrease with increasing flow rate in <br />the rivers, due to dilution from runoff. <br />• 3.2.2 Springs <br />One spring on the mine site area is being monitored under TC, the No. 1 Strip Pit Discharge. There are a few <br />other springs and local permanent "damp spots" in the area; however, their combined flow is normally less <br />than 10 gpm and is therefore not significant. The No. 1 Strip Pit Discharge is a CDPS monitoring point <br />(Outfall 022, a.k.a. site 1SP). There is no sediment pond associated with this spring. Spring water mns down <br />a narrow path through a vegetative filter and discharges directly to the Williams Fork River. The POR <br />discharges for the No. 1 Strip Pit are presented in Figure 9 and the 2005 discharge measurements are <br />presented on Figure 10, respectively. The discharge from the No. 1 Strip Pit increased significantly back in <br />1989. This may have been due to seepage from the ditch that conveys [he 7 North Angle discharge <br />(measured at site 9P3). Site 9P3 discharge began in January of 1989, and has been sporadic. Discharge rates <br />from 1990 through 2003 are lower. 9P3 did not discharge in 2004 or 2005. Nevertheless, snowmelt and ditch <br />seepage both appear to have some influence on the No. 1 Strip Pit discharge, as the discharge typically drops <br />to just a few gpm from January through May with a small peak typically in March coinciding with spring <br />mnoff. <br />The summary of the water quality data for the spring is presented in Tables 17 and 18. A plot of POR total <br />dissolved solids for the No. 1 Strip Pit is presented in Figure 11 and POR iron concentrations are presented <br />on Figure 12. Figure 11 indicates that TDS concentrations increased from an average of around 900 mg/1 in <br />• the early 1980's, to about 1500 mg(( in 1984 through 1986, stabilized to about 1,100 mg/I between 1987 and <br />2002. There has been a small increase in concentrations in 2003 through 2005 (which averaged about 1300 <br />5 <br />I:\Env\EmpireW HR\2005\Texl\Empire2005AH R.doc <br />