Water Stewardship Information Sources

ID 540
Citation Eaton, B, Moore, RD and Giles, T. 2010. Forest fire, bank strength and channel instability: the 'unusual" response o fFishtrap Creek, British Columbia. Earth Surface Processes and Landforms 35:1167-1183.
Organization UBC
URL http://onlinelibrary.wiley.com/doi/10.1002/esp.1946/abstract;jsessionid=AB77462C1B528885352962A8EB6B10A4.f04t03?deniedAccessCustomisedMessage=&userIsAuthenticated=false
Abstract/Description or Keywords forest fire;bank erosion;gravel bed steam;suspended sediment
Abstract
In August 2003, the McLure forest fire burned 62% of the drainage basin of Fishtrap Creek. Streamflow has been measured there since the early 1970s, and suspended sediment concentration and channel morphology have been monitored since the fire. Although the short post-fire period (four years) limits our ability to draw firm conclusions about streamflow changes, there has been no obvious increase in peak flows since the fire. However, the total runoff during the freshet period does appear to have increased and the onset of snowmelt appears to occur about two weeks earlier than it did prior to the fire. Suspended sediment records from Fishtrap Creek and from an unburnt reference stream nearby are similar, suggesting that the burnt areas have remained relatively stable and that the sediment supply to Fishtrap Creek has not been dramatically altered. In contrast, the stream channel morphology has changed, widening by over 100% of the original width in some places and transforming from a laterally stable plane-bed morphology to a laterally active riffle-pool morphology. The timing and magnitude of the observed morphologic changes are consistent with the predicted decline in bank strength due to root decay, implying that the observed changes are associated with an internal instability associated with changes to the stream boundaries, rather than with the more typically reported externally driven instabilities caused by changes in streamflow or sediment supply. This delayed response in the absence of large changes in streamflow or sediment supply, while ムunusual' in that it has not been documented in the previous literature, may be a common mode of response, particularly in wat'ersheds with nival flow regimes. wildfire, forest disturbance
Information Type article
Regional Watershed North Thompson
Sub-watershed if known Fishtrap Creek
Aquifer #
Comments project may be resurrected in future as funding permits, Phil Owens and UNBC group still doing some work
Project status complete
Contact Name Brett Eaton
Contact Email [email protected]