Fraser River Gravel Reach Studies
UBC Department of Geography
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 Modern developments change rivers
In most areas of the world, people and development tend to be concentrated on the floodplain of large rivers where transportation, food, and water supply needs are easily accommodated.  However, development often results in drastic changes to the morphology and ecology of rivers.  These changes can be brought about through:
  • channel confinement
  • vegetation removal (both on the banks and within the channel)
  • gravel removal
  • changes to groundwater levels under the floodplain


Contemporary British Columbia rivers are a lot different today than they were 100 years ago
In British Columbia, there is a tendency to associate river changes with logging.  However, many other activities such as flood control, water supply, land development, communication and transport also impact rivers.

Critical needs to understand large rivers in British Columbia
While there has been considerable focus on fish habitat within small streams, the ecology of large rivers remains largely uninvestigated.  Critical research needs include:

  1. learning more about how big rivers change their channel, hence habitat;
  2. learning more about fish habitat requirements;
  3. learning more about how changes in habitat affect fish populations; and
  4. learning more about maintaining ecologically acceptable conditions in rivers.
 Lower Fraser River - Gravel Reach Study
Fraser River presents a significant potential flood hazard to human settlement within the Lower Mainland of British Columbia.  With peak flows of about 10 000 m3/s or more during spring runoff, extensive areas could be flooded.  Following the great flood of 1894 (estimated at 18,000 m3/s), efforts commenced to protect developing settlements from the river.  Over the past century, an ongoing program of river dyking and bank protection has been pursued, especially after 1948.

There is concern, however, that the dykes might be too low in some locations between Hope and Mission as gravel moving from the mountains is deposited on the dyked and confined channel.  The rising channel bed increases flood hazards by reducing the flow capacity of the river.  It appears as if this problem could be readily solved by removing gravel to lower the streambed, but …

  • The reach has an exceptionally diverse aquatic ecosystem with high economic value.
  • The effect of gravel removal on these values is not understood.
  • The recreational opportunities and spiritual values of the riverscape are increasingly recognized.
The problem, then, is to find a way to manage the river which maintains the existing flood protection in a manner consistent with maintaining the ecological character of the river.  A solution to the problem of managing the gravel reach is being sought, in part, through research at the Department of Geography, University of British Columbia.
For information about the Fraser River Study, please contact any of the following:
Prof. Michael Church UBC   mchurch@geog.ubc.ca  (604) 822-6959 Darren Ham  Ph.D. candidate  fraser@geog.ubc.ca 
Funding for this project is provided by the BC Ministry of Water, Land and Air Protection, Canada Department of Fisheries and Oceans, City of Chilliwack, the Habitat Conservation Trust Fund of British Columbia, the Provincial Flood Assistance Program, Steelhead Aggregates Ltd., Indian and Northern Affairs Canada, District of Kent, the City of Abbotsford, and the Natural Science and Engineering Research Council of Canada (NSERC).