Laserfiche WebLink
results of the gauging stations along Trout Creek indicate that the monitoring program is being placed on-line early enough in <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 the variability between mild winters (winters of less snow accumulation) and harsh winters. <br />The graph showing 2001-2003 data indicates an increase in the total streamflow in 2003 from 2001 and 2002 levels. The <br />1994-2003 graph suggests that 2003 was an average winter for the pas[ decade. This was due to several late winter <br />snowstorms that occurred over the mine site in 2003. <br />The flow record for 2003 shows a high peak flow to have occurred in June as i[ did during 1995, 1997, 1998, and <br />1999. The runoff from the mine site was much higher in 2003 than in previous years due to several late season snowstorms <br />that occurred over the mine site. Unusually high flows were measured at TR-a in ]ate May- early June 2003 due to debris [hat <br />collected around [he bridge located immediately downstream of [he streamflow monitoring site during runoff The flow data <br />presented in Figure 1 consists only of information derived from continuous flow records. Instantaneous flow measurements <br />obtained between 1989 and June 1994 for this location are provided in Appendix A. Prior to that time, instability of the <br />stream channel caused by a 1984 flood precluded the installation of any type of monitoring station in the vicinity. The old <br />Stevens chart recorders were replaced with electronic streamflow recorders in April 2003. <br />The bridge located immediately downstream of TR-a was replaced in the fall of 2001 potentially altering the current <br />stage rating curve. Therefore, the decision was made to update the stage/discharge curves for TR-a and TR-b. Over the 2001 <br />season, a total of nine cross-sections and associated velocities were measured at each cross section location. This data was <br />used to compute a stage rating curve at each location. <br />The stage rating curve for TR-a was developed from flows ranging from 11 cfs to 145 cfs. The curve equation and rZ <br />for the curve are as follows: y = 44.469xs.rxoe where y =flow in cfs and x =depth of flow; rZ = 0.98. Flows for much of 2003 <br />were below the 11 cfs used to develop the rating curve; therefore, the calculated flows may to be low. <br />The stage rating curve for TR-b was developed from flows ranging from 13 cfs to 144 cfs. The curve equation and rZ <br />for the curve are as follows: y = 65,049x2.431, where y =flow in cfs and x =depth of flow; r2 = 0.99. This appears to <br />indicate a good correlation between the upstream and downstream flows. <br />2 <br />