Flood and the Fraser

With rivers come risk — including the risk of flood. For the past 20 years, the Fraser Basin Council has worked to support provincial and local authorities in carrying out their respective responsibilities for flood mitigation on the Fraser and other river systems.

Most years there is flood, or risk of flood, somewhere in British Columbia. During the 2012 spring freshet on the Fraser, Prince George, Chilliwack and Langley were among the communities that faced flooding in low-lying areas.

The risk of catastrophic loss from flood is greatest in the Lower Fraser because of a large population (over 300,000 people) and significant residential, commercial, industrial, utilities and transportation infrastructure in the floodplain. The Fraser Valley and other parts of the Fraser Basin have experienced two major floods of record, the largest in 1894 and the second largest in 1948.

Preventive planning and flood protection are critical since a major flood today would have severe social, economic and environmental consequences. These include risk of injury and loss of life, damages and loss of property, temporary loss of infrastructure and community services, disruption of business and trade, degradation of water quality and harmful impacts on fish and wildlife habitat. Phase 1 of the LMFMS estimated economic losses of $20-30 billion from a major Fraser River or coastal flood in the region between now and 2100. Learn more about the Phase 1 results.

A Look Back

Red Cross rescue during the 1948 Fraser Valley flood. Photo: Vancouver Public Library.

The largest Fraser River flood on record was in May, 1894 when rapid snowmelt caused river levels to rise dramatically, triggering flooding from Harrison to Richmond. The flood was massive; however, property damage was limited because settlement was sparse. The next largest Fraser flood of record was in 1948. Because of increased development and population growth in the floodplain, the impacts were much greater than in 1894. According to the Province of BC, this included:

• evacuation of 16,000 people
• damage or complete destruction of about 2,000 homes
• $210 million in damages (2010 dollars).

The Province also flags that recent studies show a reoccurrence of the 1894 flood could cause approximately $1 billion in economic damages to the City of Chilliwack and several billion in economic damages to the City of Richmond. Read more on the provincial Dike Management and Safety page.

Since 1948 the Fraser River has not had a flood of this magnitude, although there have been many high water events and limited floods.

Integrated Flood Management

Nature controls the timing and severity of flood events, but communities can reduce the extent of damage through floodplain bylaws, flood protection works, floodproofing measures and emergency flood plans. Combined, these activities provide an integrated approach to flood hazard management.

Today in the Fraser Basin, there are about 600 km of dikes, 400 floodboxes and 100 pump stations to protect communities and infrastructure from flooding. Although dikes and drainage are critical infrastructure, land use planning is also pivotal to minimizing risk of catastrophic loss, and this may include community decisions to limit development and infrastructure in floodplain areas.

Flood Maps for Lower Fraser and BC

See an overview map of the Lower Fraser River, with the floodplain area (illustration purposes only) coloured light blue. It is possible for flooding to occur outside the boundary area. Moreover, boundaries have since been updated in some locations following digital mapping projects of local governments in Mission, Kent, Harrison Hot Springs and Abbotsford.

If you have questions about a location in or near the floodplain, contact your local municipal hall for information. Also check out the following:

• Province of BC (designated floodplains)
• BC Ministry of Environment (Lower Mainland dike and emergency maps).

Other Resources

Flood preparedness information is available through many BC municipalities. You may also find these websites helpful:

• Provincial Emergency Program (PEP)
• River Forecast Centre
• Public Safety Canada
• Local heath authorities, including Fraser Health Authority and Northern Health Authority.