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Water Diversion

Water diversion refers to the practice of redirecting the flow of the river through purpose-built channels. Providing an alternative route for excess water reduces peak flows and lowers the chances of flooding. Diversion channels are typically built around developed communities to prevent extensive flood damage.

The Red River Floodway in Manitoba is a well-known example of water diversion for flood control. The project, completed in 1968 and expanded in 2010, redirects part of the Red River’s flow around the City of Winnipeg when needed.

Potential Benefits Potential Challenges
  • Reduces peak flows on a river 
  • Can direct water away from entire communities
  • Disrupts natural river flow
  • Diversion channels are costly to build and could have environmental and other impacts
  • Diversion channels can become blocked or overwhelmed

In BC/Lower Mainland 

In BC, a 1976 report of the Fraser River Joint Advisory Board considered a proposal to divert the flow from McGregor River to the Peace River Basin for both hydro-electric power generation and flood mitigation. The intention behind these measures was to reduce flood levels and increase the stability of the Lower Mainland dikes during a major flood event. In the end, this proposal was not pursued due to concerns over losses to commercial and First Nations fisheries, sports fishing, wildlife and recreational values, and the potential for inter-basin transfer of fish parasites.