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Flood Damage Reduction Program


The aim of the Flood Damage Reduction Program (FDRP) is to discourage future flood vulnerable development. The federal government initiated this program in 1975 to curtail escalating disaster assistance payments in known flood risk areas, as well as the reliance on costly structural measures. The FDRP is carried out jointly with the provinces under cost sharing agreements. Once a flood risk area is mapped and designated both governments agree not to build or support (e.g., with a financial incentive) any future flood vulnerable development in those areas. Zoning authorities are encouraged to zone on the basis of flood risk. New development is not eligible for disaster assistance in the event of a flood.

More than 900 communities have been mapped and designated, including all major urban centres except the lower mainland of British Columbia, at a cost of over $50 million. Many communities, especially in British Columbia, Alberta, Ontario, Quebec, Nova Scotia and Newfoundland, have been zoned on the basis of these maps. Where existing development warranted it, other activities such as flood forecasting (Saint John River Basin) and construction of structural measures (dykes in Red River Valley and Montreal) were supported under the FDRP.

To find out if you are in a flood risk area or to learn more about the program in your community, check the listings under Provincial/Territorial Flood Damage Reduction Programs.


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This term defines a flood-prone area that has been mapped indicating the limits of flood risk and, in addition, where the federal and provincial/territorial ministers approve and sign documentation declaring these areas officially as flood risk or flood hazard areas. Designation has the effect of restricting new construction in the floodway if municipalities enact zoning regulations.

There are two types of designations:

  • final designation, which means that all minimum mapping and technical standards were met; and,
  • interim designation, which means that other techniques were used.


This provision within the Quebec agreement allows the exemption of a specified area within a designation and permits the building of a specific structure within a designated floodway. Public works such as bridges, pipeline crossings, etc. require derogation. However, in other provinces this type of infrastructure development is automatically exempt.

Effective date

The date when the FDR Program policies come into effect within a designated area.

Flood Risk Area (floodway and flood fringe)

The area that has been delineated as being prone to flooding. The minimum design flood criteria standard is the 100-year flood which is the peak or flood flow with one chance in one hundred of occurring in any given year.

In some provinces, the standards are more stringent: Saskatchewan uses 500-year design flood, with an additional freeboard for hydrologic and hydraulic uncertainties; British Columbia, 200-year design flood, with an additional freeboard for hydrologic and hydraulic uncertainties; Ontario uses the 100-year design flood or regional storm events such as Hurricane Hazel which exceeds the 100-year design flood.

In most designations the flood risk area is subdivided into two zones: floodway and flood fringe. The floodway is the area where the flow is the fastest and most severe and where the potential danger is the greatest. Within the floodway most types of development are discouraged whereas within the flood fringe most types of development are permitted -- on the condition that specified flood proofing measures are undertaken.

Number of communities within designation

Often designated areas represent a length of a river reach and/or lake shoreline as opposed to simply one community. Therefore, it is possible to have more than one community within a designation.

Public information maps/key plans

For every area that becomes designated, public information maps have or will be produced. In British Columbia, key plans (essentially an index map) are produced in place of these maps. These products are for public use. Note that the more detailed engineering maps are kept at local, provincial and federal agencies.


Under the Canadian constitution, flood plain management essentially falls under the jurisdiction of the provinces, as they are primarily responsible for water resources and land use matters.

The objective of the federal government is to reduce major disruptions to regional economies and to reduce disaster assistance payments. Traditionally this had been achieved by building structural measures to control flooding. In the 1950s, 1960s, 1970s, and to a lesser extent in the 1980s, the federal government allocated millions of dollars, in conjunction with the provinces, to build dams and dykes.

Although providing some benefits, the overall cost-effectiveness of this approach was questionable, since the escalating trend of increased flood assistance payments continued. Projects of this kind are expensive to build and maintain and they are no sure guarantee against disaster. Dykes and dams can be overtopped and channel capacities exceeded making the inevitable flood worse. Structural measures often inspire a false sense of security, thereby encouraging further development in flood prone areas. Moreover this approach, as well as disaster assistance payments, has the general public paying for the benefit of the few who choose to live in known flood risk areas.

Extensive flood damages across Canada in the early 1970s clearly demonstrated that a new approach to reducing flood damage was needed. These flood events were the catalyst for the federal government to initiate the national Flood Damage Reduction Program (FDRP) in 1975 under the Canada Water Act. It represented a significant change in approach from an ad hoc structural response to flooding to a more comprehensive approach focusing on prevention and non-structural measures. It was also more equitable.


Flooding is a natural event; problems arise when it causes damages. The non-structural approach of the Flood Damage Reduction Program (FDRP) tackles the root of the problem by discouraging flood vulnerable development and promoting living in harmony with the river's natural regime.

The FDRP, undertaken jointly with the provinces, consists of identifying, mapping and designating flood risk areas, and then applying policies to discourage future flood prone development in those areas. Additional activities may include establishing flood forecasting and warning systems. In addition, some structural controls are supported as long as they are cost efficient and support the non-structural components of the Program.

All provinces and territories except Prince Edward Island and the Yukon participated in this national program through a series of cost sharing agreements. For some provinces this approach was new, while in others, such as Ontario, Alberta and British Columbia, it was an extension of mapping programs dating back, in some cases, to the 1950s.

For details on specific provincal/territorial programs visit the Provincial/Territorial Flood Damage Reduction Programs section of this site.


The Flood Damage Reduction Program (FDRP) is carried out under cost shared federal-provincial agreements. Variations exist on how the agreements are drawn up. Normally, a General Agreement outlining the policies of the Program is supplemented by a subsidiary agreement on mapping, with further sub-agreements possible on flood forecasting, structural controls and studies. In some cases, the "general" and "mapping" components are combined in one document and in the case of Ontario, all aspects of the program are in one document.

General Agreement

The General Agreement sets out the basic approach for reducing flood damages and the policies agreed upon by the two governments.

The basic approach is that where flood damage reduction measures are proposed, all practicable structural and non-structural alternatives are considered, including the option of letting some flood damage occur. Effectiveness, cost, associated benefits and environmental impact are to be accounted for in the selection of alternatives. Preference is to be given to measures that prevent flood vulnerable development.

The two governments also agree to map and designate flood risk areas in communities listed in the Mapping Agreement and apply the following policies:

  • They will not build, approve or finance flood prone development in the designated area.
  • They will not provide flood disaster assistance for any development built after the area is designated (except for floodproofed development in the flood fringe); and
  • They will encourage zoning authorities under their jurisdiction to zone on the basis of flood risk.

Mapping Agreement

The Mapping Agreement provides for a mapping program to delineate and designate flood risk areas in which the FDRP policies are applied and to inform the public of the Program. Forming part of the agreement is the list of places to be mapped. Detailed hydrologic and cartographic specifications are also included because of the important economic, social, and legal implications of the Program.

Since mapping by itself is not beneficial unless used, the public information component of the Program is the key to its effectiveness. Public information sessions are held in the effected communities throughout the mapping process. This allows the comparison of technical analysis with local flood knowledge, and ensures that target audiences are aware of and understand the Program and, more importantly, comply with its objectives and policies.

Other sub-agreements

Sub-agreements have covered flood forecasting in New Brunswick, Manitoba and Saskatchewan; structural implementation in Manitoba, Quebec and New Brunswick and other measures and studies in New Brunswick, Nova Scotia, Manitoba and Saskatchewan. All these activities have complemented the mapping / designation program.

For details, visit the appropriate Provincial/Territorial Flood Damage Reduction Programs section of this site.

Flood Risk Maps

There are two types of flood risk maps:

  1. Large scale engineering maps usually at a scale of 1:2000 or 1:5000 are used to accurately delineate the flood risk area. They are available for perusal or purchase from local offices or provincial agencies.
  2. Public information maps, with scales ranging from 1:5000 to 1:25000, are used to show the approximate location of the flood risk area and provide the public with information on the Program. They are available to the public.

The engineering or detailed flood risk maps are topographic maps that show contour lines of equal elevation and spot elevation data. The public information maps may be planimetric maps without topographic detail. In addition to cultural features such as roads, buildings, railway lines, etc., both types of maps display the designated flood risk area, the floodway if determined (see Criteria for flood risk area delineation), and occasionally the extent of historic flood events.

Visit the Provincial/Territorial Flood Damage Reduction Programs section of this site, for information on how to obtain or view a specific flood risk map.

Criteria for flood risk area delineation

The federal minimum criterion for defining the flood risk area is the 100 year flood, i.e., a flood that has one chance in one hundred of being equaled or exceeded in any given year. However, the federal government adopts provincial criteria if they are more stringent. For example, in British Columbia the 1 in 200 year flood is used, in Saskatchewan the 500-year flood is used, and in parts of Ontario a "regional storm" or highest observed flood is used.

Flood risk areas are usually divided into two zones: floodway and flood fringe. The floodway is that portion of the river's flood plain where waters are deepest, fastest and most destructive. Future development is discouraged in the floodway due to the likely danger to life and damage to property, and because the buildings themselves, by acting as obstructions, could increase flood levels upstream. Within the flood fringe, where water tends to be shallower and slower than in the floodway, new development may be permitted, provided it is adequately flood proofed.


Designation means that the Minister of the Environment, on behalf of Canada, and his/her provincial/territorial counterpart have agreed on the area, and an effective date, to which the FDR policies discouraging future flood vulnerable development will apply. To formally complete the process, the Ministers sign designation forms that also note the effective date of designation. The designated area is shown clearly on a flood risk map. In some provinces, the Ministers' signatures and date of designation are applied to a "designation block" on the map.

From the date of designation onwards policies outlined in the General Agreement are applied. For instance:

  • neither government will build structures subject to flood damage in that area;
  • government agencies such as Canada Mortgage and Housing Corporation will no longer help finance new flood vulnerable developments there; and,
  • disaster assistance programs will no longer cover losses due to flooding of new developments in the area.

Flood Damage Reduction on Aboriginal Lands

In 1985, the departments of Environment and Indian and Northern Affairs signed a Memorandum of Understanding (MOU) Respecting Flood Risk Mapping of Indian Reserve Lands and Other Lands Set Aside or Held for Indians. Under this MOU, studies have been conducted to identify priority flood prone areas, and 44 mapping projects have been undertaken.

Municipal Collaboration

Local governments play an important role in flood plain management, since they are generally responsible for land use planning and regulation of new development. The FDR agreements require that local authorities be encouraged to zone according to flood risk in designated areas. In some provinces, the local levels of government are required to incorporate flood hazard information into municipal planning through official plans, zoning bylaws, subdivision plans, and flood and fill regulations.

Provincial/Territorial Flood Damage Reduction Programs


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