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' the year to record Flow prior to the peak runoff period for each year. The individual data points show the monthly average Flows and give some indication of the variability between mild winters (winters of less snow accumulation) and harsh winters. ' The graph showing 1997-1999 data indicates a decrease in the total streamFlow in 1999 from 1997 and 1998 levels. The 1990-1999 graph suggests that 1994 was the driest winter over the past decade and 1993 was the wettest for the watershed. ' The flow record for 1999 shows the peak Flow to have occurted in June as it did during 1988, 1989, 1990, 1991, 1993, 1995, 1997 and 1998. The later peak flows for these years were probably due to more harsh winters or the on-set of t warmer temperatures occurting later in the spring. The runoff peak at TR-b in June 1999 is lower than in 1997 or 1998 due to less snowpack on the mine site in 1999. Beaver activity downstream of TR-b in September 1999 resulted in artificially high water levels and flow rates for that period. ' The stage/flow rating curve for TR-a was reviewed in June of 1994 to ensure its continued accuracy. Sufficient differences in the channel cross-section at TR-a were noted during the review to wartant development of a new stage/Flow ' rating curve. Over the 1994-1995 seasons, a total of five cross-sections were developed and compared to ensure channel stability. An averaged cross-section was then developed to compute a stage/rating curve. The stage rating curve data covered ' flows ranging from approximately two cfs to 85 cfs. The equation and rZ for the curve are as follows: y = 13.817x~~~bsfi, where y =Flow in cfs and x =depth of Flow; r2 = 0.98. During 1999, cross-section measurements were taken to confirm that the ' channel configuration had remained stable during the past annual monitoring period. Flow data for TR-b consists of both instantaneous flow and continuous flow measurements. The Flow data presented in Figure I consists only of information derived from continuous Flow records. Instantaneous Flow measurements obtained between 1989 and June 1994 for this location are provided in Appendix A. Prior to that time, instability of the stream channel caused by a 1984 Flood precluded the installation of any type of monitoring station in the vicinity. ' Instantaneous flow measurements were recorded at TR-b during 1989 in conjunction with water quality samples taken at TR-D, except for the October sampling period. Between the sampling periods of September and October in 1989, ' beaver activity both above and below TR-b occurted causing the location of TR-b to become pan of an inundated beaver pond. High Flows destroyed the staff gauge at TR-bin 1990 and again in 1991. As a result, no instantaneous streamflow data ' was collected in 1990, while 1991 had one measurement in May. Between April 1992 and July 1993 Flow measurements and water samples were collected on the same day at TR-b and TR-D, respectively. However, between the sampling periods of July and August, 1993, beaver activity had resumed ' below TR-b rendering the station unsuitable as a Flow monitoring location. In June 1994, a continuous flow monitoring station was installed a[ a new location downstream of the previous ' location. Calibration flow and cross-section measurements were taken during 1994 and 1995 to develop astage/flow rating curve for this location. ' Over the 1994-1995 seasons, a total of five cross-sections were developed and compared to ensure channel stability. An averaged cross-section was then developed to compute astage/rating curve. The stage rating curve data covered Flows ranging from approximately I I cfs to 120 cfs. The equation and rt for the curve are as follows: y = 57.092x~ 125, where y = ' Flow in cfs and x =depth of flow; r' = 0.98. As at TR-a, cross-section measurements were taken at TR-b during 1999, which verified that the channel configuration had remained stable. Flow measurements for TR-a and TR-b are in Appendix A. 1 ' 2