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RIVERS <br />• <br />FLOWS <br />The Williams Fork River flow data is collected by the U.S. Geologic Survey at one continuous gaging station <br />and one staff gage. The Williams Fork River continuous gaging station (WF-2) is near the conFluence with <br />the Yampa River, downstream of the #5 Mine discharge. The staff gage (WF-1) is located upstream of the <br />mine discharge points. <br />The flow data for Station WF-2 for 1991 was taken from magnetic format data provided by the USGS. A <br />summary of the staff gage readings for 1991 is presented in Table 29. A plot of daily mean flow versus time <br />for the Williams Fork River for 1991 is presented in Figure 25. The plot for the Williams Fork River includes <br />the mean monthly (lows for the Williams Fork at Hamilton (a discontinued USGS gaging station). <br />For the Williams Fork River at Cyprus Empire Corporation, flows measured by the USGS during calendar <br />• year 1991 showed a maximum daily flow of 1620 cfs and a minimum daily flow of 30 cs. Monthly minimum, <br />maximum and mean flows are plotted for each month of record in Figure 26. The (lows in the Williams Fork <br />River during 1991 appear normal for the period of record and very similar to year 1988. Flows were below <br />normal in the two preceding years, 1989 and 1990. These flows including comparison between upgradient, <br />WF-1, and downgradient, WF-2, measured to date, do not show any stream depletion impacts from mine <br />dewatering. <br />WATER QUALITY <br />Summaries of the water quality data are presented in Tables 30 through 33. A plot of upstream and <br />downstream field electrical conductivity measurements for the river is presented in Figure 27. The data <br />indicates that the surtace water quality does not show any significant variation from expected values. <br />Conductivity increased near the end of 1991. Nevertheless, the increase was observed simultaneously at <br />• 8 <br />