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Sununaries of the available water quality data for the mine discharge sites aze presented in Tables 7 through <br />10. The plot of dissolved solids presented in Figure 5 shows that the average dissolved solids in the Eagle <br />No. 5 Mine discharge water have increased slightly from about 800 mg/1 in 1982 and 1983 to 882 mg/1 in <br />2003. Simifazly, the average dissolved solids concentration for the 7 North Angle was 1100 mg/1 in 2003 <br />(Note: oniy one sample was analyzed for TDS in 2003 due to limited flow occurring only during the end of <br />the third quarter), which is a return to values common in 1994 and 1995. Water levels for the 7 North Angle <br />well are monitored on a quarterly basis. This data is presented in Table 9A. <br />3.1.3 ALLUVIAL WELLS <br />Water quality in the Williams Fork River Alluvium is monitored via alluvial well AVF-5, which is located <br />adjacent to the underground discharge sediment ponds area (See Figure 2). Under TC, AVF-5 is measured for <br />water level and field parameters on an annual basis (between July 20th and August 30th) concurrent with the <br />Williams Fork surface water sampling (site WF-1). No water quality analyses are required for AVF-5 under <br />TC. <br />Historically, groundwater levels in the alluvium have remained fairly regular, with normal seasonal <br />fluctuations, apparently related to changes in river levels. POR groundwater levels in AVF-5 are plotted in <br />Figure 6. The data indicates no impact on alluvial water levels related to mining. <br />• Field parameter data for AVF-5 for 2003 is presented in Table 11. POR water quality data is provided in <br />Table 12. A plot of field electric conductivity versus time is presented in Figure 7. There has been no <br />conclusive evidence of seasonal variation of water quality in the alluvium. AVF-5 was within historic levels <br />in 2003. <br />3.2 Surface Water Monitoring <br />3.2.1 Rivers <br />There are two rivers in the vicinity of the mine site. The Yampa River, flows in a southeasterly direction <br />across the mine site. The Yampa River drains most of the northeast comer of Colorado and part of south- <br />central Wyoming. The second river is the Williams Fork, which is a major tributary of the Yampa River. The <br />Williams Fork River joins the Yampa River on the mine property. Monitoring data is collected for the <br />Williams Fork River. <br />The United States Geologic Survey (USGS) had one gaging station and one staff gage for collection of <br />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 water quality <br />analysis (See Table 3). WF-2 is also monitored concurrent with WF-1. <br />4 <br />I:\Env\EmpireW HR\2003\Text\Empire2003AHR.doc <br />