Laserfiche WebLink
Williams Fork River flow data. The Williams Fork River gaging station (WF-2) is neaz 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 />The flow data for WF-2 was historically provided by the USGS, however, monitoring of the Williams Fork <br />stations was discontinued in ZOOI. Historically, comparisons between up gradient site WF-1, and down <br />gradient site WF-2, did not show any stream depletion impacts from none dewatering. <br />Summaries of WF-I 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 mnoff. <br />3.2.2 Springs <br />One spring on the mine site area is being monitored under TC, the No. 1 Strip Pit Discharge. The No. 1 Strip <br />• Pit Discharge is a CDPS monitoring point (Outfall 022 or 1SP). There are a few other springs and local <br />permanent "damp spots" in the area; however, their combined flow is normally less than 10 gpm and is <br />therefore not significant. The POR discharges for the No. 1 Strip Pit are presented in Figure 9 and the 2002 <br />discharge measurements are presented on Figure 10, respectively. The discharge from the No. 1 Strip Pit <br />increased significantly in 1989. This may have been due to seepage from the ditch that conveys the 7 North <br />Angle discharge. The 7 North Angle discharge began in January of 1989. However, discharge rates from <br />1990 through 2002 appear lower. Nevertheless, snowmelt and ditch seepage both appear to have some <br />influence on the No. 1 Strip Pit discharge, as the discharge typically drops to just a few gpm from January <br />through May with a small peak typically in March coinciding with spring runoff. <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 the dissolved solids of the discharge has increased from an average of <br />approximately 900 mgA in 1982 and 1983 to almost 1,400 mgA in 1986, and then decreased to approximately <br />1,000 mgQ since 1987. Figure 12 illustrates the variable nature of total recoverable iron concentrations in the <br />No. 1 Strip Pit discharge. During 2002, these levels remained within typical ranges seen for this site. <br />3.2.3 Ponds <br />• There was no discharge from the sediment ponds in 2002. <br />5 <br />1:1EnvlEmpiretAHR120021TextlEmpire2002AHR,doc <br />