Water Stewardship Information Sources

Citation Ferguson, R. I., Bloomer, D. J. and Church, M. (2011), Evolution of an advancing gravel front: observations from Vedder Canal, British Columbia. Earth Surf. Process. Landforms, 36: 1172–1182. doi: 10.1002/esp.2142
Organization UBC
URL http://onlinelibrary.wiley.com/doi/10.1002/esp.2142/abstract
Abstract/Description or Keywords gravel–sand transition;aggradation;bimodality;selective transport;sediment patches
Channelization of the lowermost part of Vedder River in 1922 initiated a natural experiment relevant to the unresolved question of how abrupt gravel–sand transitions develop along rivers. The new channel (Vedder Canal) had a fine bed and a much lower slope than the gravel-bed river immediately upstream. Changes in morphology and sedimentology as gravel advanced into and along the Canal are documented using air photos, historical surveys, and fieldwork. The channel aggraded and steepened until stabilized by occasional gravel extraction in recent decades. The deposited material fines progressively along the Canal but the gravel front has retained an abrupt appearance because it has advanced by the sequential development of discrete gravel tops on initially sandy alternate bars. Near the gravel front the bed is highly bimodal and there is a sharper drop in the extent of gravel-framework surface facies than in bulk gravel content. Ahead of the front, gravel is restricted to thin ribbons which often become buried by migrating sand. Calculations show that even though the gravel bed at the head of the Canal is almost unimodal, size-selective transport during floods can account for the strong bimodality farther downstream.
Information Type Article
Regional Watershed Lower Fraser
Sub-watershed if known
Aquifer #
Project status complete
Contact Name Michael Church
Contact Email [email protected]