Frequently Asked Questions
A look down on part of the Fraser Valley floodplain.
Questions on Fraser River Flood Hazard Management
What is the role of the Fraser Basin Council in flood hazard management?
What types of flood hazards exist along the lower Fraser River?
What causes Fraser River flooding?
What is the risk of flood on the Fraser in 2007? Where can I get up-to-date information?
I've heard that the dikes on the Lower Fraser are not high enough to withstand a major flood. Is that true?
What is being done to address the flood risk?
Where can I get more information on flood hazard management?
Questions on Emergency Preparation and Response
How do I know if I am in the floodplain? Where can I find online ?
If a flood were to occur, what is the emergency response?
What can residents do to prepare for a possible flood?
What can agricultural producers do to protect livestock?
What if flood occurs and there is property damage? Is there compensation?
How much monetary assistance is available under the Disaster Financial Assistance Program?
Questions on Fraser River Flood Hazard Management
What is the role of the Fraser Basin Council in flood hazard management?
The Fraser Basin Council (FBC) is a not-for-profit, non-governmental organization that works to advance sustainability in the Fraser Basin and its communities.
The FBC has no jurisdiction or authority to manage flood hazards, which is the role of government authorities. Our role is to develop and share information on flood hazards and to work with government agencies to address flood management issues and concerns. We bring together the jurisdictions that have roles and responsibilities to facilitate dialogue and build consensus on how flood hazard management strategies can be better coordinated and integrated.
What types of flood hazards exist along the lower Fraser River?
There are many different flood hazards throughout the Fraser Basin and BC:
- Local flood risks: Communities can face floods from smaller streams and rivers overtopping their banks, and from drainage systems such as storm sewers, reaching capacity. This type of flooding can result from heavy rainfall events.
- Spring flood risks: The most significant flood concern on the Fraser River comes from high water during spring snowmelt (also known as spring freshet). The flood of 1894, in the Fraser Valley and Lower Mainland, is largest flood of record. It is considered the "design flood" on which flood protection and floodplain management is based. The second largest Fraser River flood was in 1948.
- Winter flood risks: For those communities of the Lower Fraser that sit along the coast, the dominant flood risk is a winter storm surge originating in the Strait of Georgia. The estimated 1-in-200 year storm surge is considered the design flood for communities and dikes downstream of the Alex Fraser Bridge.
- Tsunami flood risk: If a Tsunami (large waves following an earthquake) were to occur off the coast of BC, there is also potential for flooding in coastal communities of the Lower Fraser.
What causes Fraser River flooding?
Floods are natural events that occur when water levels rise higher than natural embankments and human-built dikes can contain. Major flooding of the Fraser River is triggered by a combination of factors:
- High moisture level in soil before snowmelt
- High proportion of water in the snow pack
- Cold spring and cool early summer that delays snowmelt
- Rapid, large, sustained rise in temperature without nightly freezing at high elevations
- Rain during snowmelt adding to runoff and increasing the rate of snowmelt.
What is the risk of flood on the Fraser in 2007? Where can I get up-to-date information?
The BC River Forecast Centre monitors and reports on snowpack conditions in BC, and is the best source of information on flood risks. The Water Survey of Canada provides near real-time streamflow and/or water level information for many sites throughout BC, and these data are used to assist in forecasting.
In 2007 the River Forecast Centre reported very substantial snowpacks have accumulated over large parts of the province. As a result, the Centre predicted well above normal spring run-off in most river basins and a signficant potential for flooding in some areas, including on the Fraser River and its tributaries. The risk of flood depends on many factors (see above). During this year's freshet, there was flooding in parts of the Upper Fraser (as well as in other river systems in Northern BC), but the Lower Fraser has been spared flooding as a result of favourable weather conditions.
For updates, visit the River Forecast Centre, at www.env.gov.bc.ca/rfc/index.htm.
I've heard the dikes on the Lower Fraser River are not high enough to withstand a major flood. Is that true?
Many communities of the Lower Fraser River rely on dikes to protect low-lying areas. A hydraulic modelling study by the Fraser Basin Council for the BC Ministry of Environment, completed in November, 2006, found that the Fraser River dikes would not be high enough in many locations to withstand a flood equivalent to the largest flood on record (in 1894).
The study has predicted the water levels that would be associated with a major flood on the Lower Fraser to provide an up-to-date design flood profile. The dikes were built to a height that reflects an earlier flood profile from 1969.
The recent FBC study was based on two scenarios: (a) a flood equivalent to the 1894 Fraser River freshet flood, combined with spring high-tide conditions (Fraser freshet profile), and (b) a one-in-200-year winter storm surge flood with winter high tide conditions combined with a Fraser River winter flow (the winter storm surge profile).
In November, 2006 the results of the study were released. The flood profile computed by this model is higher than the original 1969 flood profile used for dike design and construction. As a result, the study found that widespread dike overtopping and dike failures would occur throughout the Lower Fraser River in the event of a re-occurrence of the 1894 flood of record. The study found that diking systems from Chilliwack to Surrey and from Kent to Coquitlam would be overtopped at one or more locations, and the Delta dike at Fraser Shore would be overtopped at one location. Freeboard for a winter storm surge flood would be inadequate in Delta and Richmond.
The Province of BC has recently taken new steps to address the flood risk: see What is being done to address the flood risk?
Details of the FBC Flood Study
To see the results of the hyraulic model, see News Release/Backgrounder and Summary of Results.
The full study, in four volumes, has been posted on the BC Ministry of Environment website.For more information, contact Program Manager Steve Litke at 604 488-5358 or slitke@fraserbasin.bc.ca.
What is being done to address the flood risk?
The Province of BC accepted the results of the FBC study and adopted a new flood profile for dike design and construction. In March, 2007 the Province provided $33 million for diking authorities throughout BC to undertake urgent flood mitigation works that could be completed prior to the 2007 spring freshet.
In the longer term, it is important to ensure that flood hazard management, including dike rehabilitation and other flood protection works, be given priority.
The most effective long-term method of flood hazard management is to regulate development on the floodplain, through the co-operation of all levels of government, developers, builders, realtors and the public. Land use decisions by local governments must take into account flood risks to ensure that development occurs on the least hazardous lands. The purpose of flood hazard management program is to ensure public safety and protection of property through: increased public awareness of flood hazards, establishment of floodproofing standards for new development, local government land use planning, and regulation of subdivision approvals.
Where can I get more information on flood hazard management?
The BC Ministry of Environment provides information on their website. Visit www.env.gov.bc.ca/wsd/public_safety/index.html
Questions on Flood Preparation and Emergency Response
How do I know if I am in the floodplain? Where can I find maps?
For an overview of the Fraser River floodplain, see Fraser River floodplain map: Low resolution / Medium resolution.
Provincial maps online
More detailed maps containing floodplain information are available at:
* BC Ministry of Environment (floodplain maps)
* BC Ministry of Environment (Lower Mainland dike and emergency maps)
* BC Ministry of Environment (BC Water Resources Atlas, including flood protection works)
Local maps and information hot lines
Local governments offer information on emergency plans for their communities, including online information. Many also posted information on the 2007 flood risk, and made local floodplain maps available. Please check with your local government for more information.
The FBC has recently overseen new floodplain mapping projects requested by local governments in Mission, Abbotsford, Harrison Hot Springs and Kent in 2006 and 2007. Residents interested in more information should contact those municipalities.
If a flood were to occur, what is the emergency response?
Local authorities are responsible for local emergency plans and for the first response to emergency situations in their communities. For up-to-date information on the plans in your community, and any advisories, please monitor local media and visit your local government website. Some local governments have posted special web pages addressing flood risks and emergency plans: see above .
The BC Flood Plan, prepared by the Province of BC, establishes the organization, roles and responsibilities of provincial government agencies in responding to floods and sets out how they coordinate with local government. The intent of the Plan is to ensure public safety, and to protect environmental resources and commerce from flood events by providing for safe, timely, effective, and coordinated response. For details, see: 2007 BC Flood Plan.
What can residents do to prepare for a possible flood?
There are a number of steps you can take to prepare for a possible flood, safeguard your family and reduce potential flood damage to property and possessions.
First, contact your local government to ensure that you have locally relevant flood information, including how authorities plan to provide provide updates to residents and businesses within the community on the flood risk or emergency plans.
Second, if your home or business is in or near the floodplain, prepare in advance to secure your property, make arrangements for a place you and family members can stay, and prepare for a possible evacuation. The Provincial Emergency Program (PEP) offers information to help individuals make personal preparations for a flood or other emergency: www.pep.gov.bc.ca/index.html.
Some examples of personal preparedness for an imminent flood event include shutting off water and power supplies; plugging all sewage and drainage connections; elevating electrical appliances, hazardous materials, and household valuables to high levels if possible; and prepare for possible evacuation by organizing personal items such as food, water, clothing, prescription medication; sleeping bags, personal identification, cash and credit cards, flashlight, a battery-operated radio and extra batteries.
What can agricultural producers do to protect livestock?
Agricultural producers will wish to plan for care of their livestock during emergencies, such as flood. The Ministry of Agriculture issued information on April 18, 2007 to assist agricultural producers, both inside and near the floodplain, in protecting their livestock: see www2.news.gov.bc.ca/news_releases_2005-2009/2007AL0012-000470.pdf
What if a flood occurs and there is property damage? Is there compensation?
Provincial government assistance is available to homeowners and renters; small businesses; farm operators; charitable and non-profit organizations; local government and provincial ministries. The Disaster Financial Assistance Program provides funds to replace or restore items essential to a home, livelihood or community service. Loss or damage to items for which insurance was reasonably and readily available is excluded. Recreational / seasonal residences, luxury goods, recreational items including rec rooms, damage to landscaping and land lost through erosion are not covered by the program.
How much monetary assistance is available under the Disaster Financial Assistance Program?
There is a $1,000 deductible taken off the total claim with 80% of the balance payable to the claimant. The maximum amount payable per claim is $300,000 for homes, businesses, farms and charitable organizations. A claim may be submitted for more than one category. Claims may not exceed the cost of restoring items and property to their immediate pre-disaster condition. For details, please see Disaster Financial Assistance on the BC Provincial Emergency Program website.
