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1 <br /> <br /> <br />1 1 <br /> <br /> <br /> <br /> <br />1 <br />1 <br /> <br /> <br />the year to record flow prior to the peak runoff period for each year. The individual data points show the monthly average <br />flows and give some indication of thz variability between mild winters (winters of Izss snow accumulation) and harsh wieners. <br />The graph showing 1998-2000 data indicates a decrease in the total streamtlow in 2000 from 1998 and 1999 levels. The <br />1991-2000 graph suggests that 2000 was the driest winter over the past decade and 1993 was the wettest for the watershed. <br />The flow record for 20(10 shows the peak flow to have occurred in May as it did during 1991, 1992. 1994, and 1996. <br />The earlier peak flows for these years were probably due to mild winters or the on-set of warmer temperatures occurring <br />earlier in the spring. The runoff peak at TR-b in May 2000 was artificially high due to beaver activity downstream of the <br />gauging station. However, the runoff from the mine site was much lower in 2000 than in 1997 or 1998 due to less snowpack <br />on the mine site. <br />The stage/Flow rating curve for TR-a was reviewed in June of 1994 to ensure its cominuzd accuracy. Sufficient <br />differences in the channel cross-section at TR-a were noted during the review to warrant development of a new stage/Flow <br />rating curve. Over the 1994-1995 seasons, a total of five cross-sections wire developed and compared to ensure channel <br />stability. An averaged cross-section was then developed to compute astage/rating curve. The stage rating curvz data covered <br />m)n <br />flows ranging from approximately two cfs to 85 cfs. The equation and r for the curve are as follows: y = 13.817x ,where <br />y =flow in cfs and x =depth of flow; rt = 0.98. During 2000, cross-section measurements were taken to confirm that the <br />channel configuration had remained stable during the past annual monitoring period. However, after the 2000 survey was <br />completed, road crews installed a new crossing over Trout Creek immediately downstream of the gauging station. Therefore, <br />a new rating curve will be developed for TR-a during the 20111 season. <br />Flow data for TR-b consists of both instantaneous flow and continuous flow measurements. The flow data presented <br />in Figure I consists only of information derived from continuous Flnw records. Instantaneous Flow measurements obtained <br />between 1989 and June 1994 for this lucation are provided in Appendix A. Prior to that time, instability of the stream channel <br />caused by a 1984 flood precluded the installation of any type of monitoring station in the vicinity. <br />Instantaneous slow measurements were recorded at TR-b during 1989 in conjunction with water quality samplzs <br />taken at TR-D, except for the October sampling period. Between the sampling pzriods of September and October in 1989. <br />beaver activity both above and below TR-b occurred causing the location of TR-b ro become pan of an inundated beaver <br />pond. High Flows destroyed the staff gauge at TR-b in 1990 and again in 1991. As a result, no instantaneous streamflow data <br />was collectzd in 1990, while 1991 had one measurement in Muy. <br />Between April 1992 and July 1993 flow measurements and water samplzs were collected on the same day at TR-b <br />and TR-D, respectively. However, between the sampling pzriods of July and August, 1993, beaver activity had resumed <br />below TR-b rendering the station unsuitable as a flow monitoring location. <br />In June 1994, a cominuous Flow monitoring station was installed at a new location downstream of the previous <br />location. Calibration flow end truss-section measuremems were taken during 1994 and 1995 to develop astage/Slow rating <br />curve for this location. <br /> <br />