Final flood studies and maps

Overview

The potential for flooding exists along all streams and lakes in Alberta. To assist communities in keeping Albertans safe and protecting their properties from floods, the Government of Alberta manages the production of flood studies and maps under the Flood Hazard Identification Program.

View final flood maps

Alberta’s Flood Awareness Map Application is the best way to view, interact with, and get more information about flood maps.

The flood maps available through the application are part of detailed engineering studies and were developed using the best data available when a study was conducted. The applications contains more information about specific flood studies and how to get copies of final reports. Flood maps are not available in all communities and flood risks exist in areas without flood mapping.

Types of flood maps

Flood maps identify where water will flow during a flood, and what land could be flooded for different sized floods. Most flood maps focus on floods caused by high river flows, typically experienced in spring or following summer rainstorms, but they can also show areas at risk from ice jam floods or document the extent of historic floods. Flood maps support emergency response during a flood and can help build resilient communities over the long term.

View the following videos to learn more:

• River flow basics
• Flood mapping basics

Flood Hazard Maps

Flood hazard maps define floodway and flood fringe areas for the 1:100 design flood. These maps are typically used for long range planning and to make local land use decisions, and are available to all levels of government and the public to help build resilient communities.

Flood Hazard Area

The flood hazard area is the area of land that will be flooded during the 1:100 design flood. The flood hazard area is typically divided into two zones, the floodway and the flood fringe.

Floodway

The portion of the flood hazard area where flows are deepest, fastest and most destructive. The floodway typically includes the main channel of a stream and a portion of the adjacent overbank area. New development is typically discouraged in the floodway.

Flood Fringe

The portion of the flood hazard area outside of the floodway. Water in the flood fringe is generally shallower and flows more slowly than in the floodway. New development in the flood fringe may be permitted in some communities and should be flood-proofed.

Design Flood

The minimum design standard in Alberta is the 1:100 flood, which is defined as a flood whose magnitude has a 1% chance of being equalled or exceeded in any year. The design flood can also reflect 1:100 ice jam flood levels or be based on a historical flood event.

Flood Inundation Maps

Flood inundation maps show areas at risk for different sized floods, including ice jam floods in some communities. These maps also identify areas that could be flooded if local berms fail, and are typically used for emergency response planning and to inform local infrastructure design.

Older flood studies include maps for as many as three flood scenarios, including the 1:100 flood. Newer studies include maps for as many as thirteen scenarios, from the 1:2 flood to the 1:1000 flood. Flood inundation maps in the same area may be available for smaller or larger floods.

Flood Likelihood Maps

Flood likelihood maps illustrate cumulative flood risk over 30 years. Different sized floods can occur any year, but smaller floods tend to occur more often than larger floods over time. These maps do not show areas protected behind flood berms unless water levels are higher than the berms.

Flood Range Maps

Flood range maps compare two different sized floods, and help communicate what parts of a community can become at risk as flows change during a flood event. Protected areas at risk behind flood berms are only shown for the larger flood being displayed, but may also exist for the smaller flood.

Contact

Connect with the Provincial Flood Hazard Identification Program:

Hours: 8:00 am to 5:00 pm (open Monday to Friday, closed statutory holidays)
E-mail: [email protected]