| Abstract/Description or Keywords |
Nine submersible pressure transducers were installed at various locations in a study reach of Fishtrap Creek during the 2006 freshet. The channel morphology of the reach underwent a moderate change in 2006, due to the effects of the McLure forest fire which, in 2003, killed all of the riparian vegetation in the study reach and burned about 62% of the Fishtrap Creek watershed. By examining the changes in the rating relations between the water stage recorded by the pressure transducers and the discharge measured at a Water Survey of Canada gauging station located just downstream of the study reach, we were able to determine the timing of morphologic changes in the stream over the course of the freshet. Shifts in the rating curve were identified by first graphically analysing the stage-discharge relations, and then constructing stage discharge regressions for that part of the record for which the rating relation appeared to be stable. The residuals associated with the calculated rating equations were then computed for the entire period of record, and used to assess the temporal pattern of changes in the rating relation. The analysis shows that the largest changes in the rating relation occurred in the vicinity of the largest morphologic changes (as determined by analysis of repeated cross-sectional surveys) and that, in areas where the morphology was nearly stable, the rating relation remained relatively stable. The sensitivity of the rating relations to changes in the channel morphology suggests that deployment of submersible pressure transducers may be a suitable and cost-effective means for monitoring channel stability near existing gauging stations or stable control cross-sections where the rating relation is unlikely to change. wildfire, channel, geomorphology |
