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<br /> <br /> <br /> <br />1 <br />1 <br /> <br /> <br /> <br />1 <br /> <br />The flow data for Station WF-2 for 1990 was taken from magnetic <br />format data provided by the USGS. <br />A summary of the staff gage readings for 1990 is presented in Table <br />29. A plot of daily mean flow versus time for the Williams Fork <br />River for 1990 is presented in Figure 25. The plot for the <br />Williams Fork River includes the mean monthly flows for the <br />Williams Fork at Hamilton (a discontinued USGS gaging station). <br />For the Williams Fork River, the maximum mean daily flow was 690 <br />cfs, the minimum mean daily flow was 14 cfs, and the mean flow was <br />117 cfs. A plot of minimum mean monthly and maximum mean monthly <br />flows, measured by the USGS for the Williams Fork River at Cyprus <br />Empire Corporation, is presented in Figure 26. The flows in the <br />Williams Fork River were below normal in 1989 and 1990. These <br />flows, measured to date for Cyprus Empire Corporation, do not show <br />any significant variation from expected values. <br />WATER QUALITY <br />Summaries of the water quality data are presented in Tables 30 <br />through 33. A plot of upstream and downstream field electrical <br />conductivity measurements for the river is presented in Figure 27. <br />The data indicates that the surface water quality does not show any <br />significant variation from expected values. The data from the <br />upstream and downstream station on the Williams Fork River indicate <br />that there is little to no detectable effect of mining on river <br />water quality. As expected, conductivity decreases with increasing <br />flow rate in the rivers. This is due to the effects of snow melt <br />and high rainfall diluting the water. <br />' SPRINGS <br />FLOWS <br /> <br /> <br /> <br />1 <br /> <br /> <br /> <br />One spring on the mine site area is being monitored. The spring <br />is the #1 Strip Pit Discharge. The A'1 Strip Pit Discharge is a <br />NPDES monitoring point. There are a few other springs and local <br />permanent "damp spots" in the area; however, their combined flow <br />is normally less than 10 gpm and are, therefore, not significant. <br />The measured discharges for the //1 Strip Pit are presented in <br />Figure 28. The discharges show a normal seasonal runoff period, <br />with low flows in the winter and early spring. Many of the flows <br />were so low, in part due to freezing, that they become too low to <br />measure. <br />The average discharge from the ql Strip Pit in 1990 was 19 gpm. <br />The discharge from the ql Strip Pit increased significantly in 1989 <br />but decreased in 1990. This is probably due to changes in seepage <br />from the ditch that conveys the 7 North Angle discharge. The 7 <br />North Angle discharge began in January of 1989. Also, the data for <br />the period from February 21, 1989 to May 9, 1989 is estimated, due <br />to problems with the flow measurement device. <br />-4- <br />