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 under the provincial Flood Hazard Identification Program.

Flood studies include detailed engineering reports and flood maps. The engineering reports are typically technical in nature and document the data, assumptions, and results of the hydrologic and hydraulic analyses required to create flood maps. Flood maps are created by combining hydraulic model results for different sized floods with high-accuracy ground information.

Provincial flood studies are prepared using the best tools and information available when a study is conducted and in accordance with technical guidelines and generally accepted engineering practices. Please contact us to obtain the most recent version of the Flood Hazard Identification Program technical guidelines.

About flood maps

Flood maps identify where water will flow during a flood, and what land could be flooded during different sized floods. Most flood maps focus on floods caused by high river flows when water escapes the river channel, most often 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.

View the following videos to learn more about river flows and flood mapping:

Provincial flood maps are used by all levels of government, consultants, industry, non-government organizations and the public. Flood maps can inform local land use planning decisions, emergency management operations and sustainable floodplain function initiatives. Flood maps are not available in all communities and flood risks exist in areas without flood mapping.

Types of flood maps

Different types of flood maps serve different purposes. Some flood maps support emergency response during a flood and other flood maps can be used to help build more resilient communities over the long term.

  • Flood hazard maps

    Flood hazard maps define floodway and flood fringe areas for the 1:100 design flood and are typically used by communities for planning or to help make local land use and development decisions. Flood hazard maps can also illustrate additional information for communities to consider, including incremental areas at risk for floods larger than the 1:100 design flood, such as the 1:200 and 1:500 floods.

    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 main zones, the floodway and the flood fringe, and may include additional flood fringe sub-zones.

    Floodway

    When flood hazard maps are produced for the first time, the floodway typically represents the area of highest hazard where design flood flows are deepest, fastest, and most destructive. When flood hazard maps are updated, the new floodway might not change and can be the same size as the previous floodway even when the flood area gets larger, to help maintain regulatory certainty for landowners.

    Flood fringe

    The flood fringe is the part of the flood hazard area outside of the floodway. When flood hazard maps are produced for the first time, water in the flood fringe is typically shallower and flows more slowly than in the floodway. Depending on when a flood study was conducted, the flood fringe can also include high hazard flood fringe, protected flood fringe, or overland flow (flood fringe) sub-zones.

    High hazard flood fringe

    The high hazard flood fringe identifies areas within the flood fringe with deeper or faster moving water than the rest of the flood fringe. High hazard flood fringe areas may be more prevalent in communities with updated flood hazard maps, but they are included in flood hazard maps from all newer flood studies.

    Overland flow (flood fringe)

    The overland flow (flood fringe) is a legacy flood fringe sub-zone that identifies areas where flooding is expected but where there is uncertainty about flood levels and water depths. These areas are only defined in a small number of older flood studies and will be phased out as those studies are updated and replaced.

    Protected flood fringe

    The protected flood fringe identifies areas that could be flooded if dedicated flood berms fail or do not work as designed during the 1:100 design flood. These areas are not expected to be flooded but reflect areas of residual risk. Protected areas can be different for floods smaller or larger than the design flood.

    Design flood

    The minimum design flood standard in Alberta is the 1:100 flood, which is defined as a flood whose flow has a 1% chance of being equalled or exceeded in any year. The design flood can also reflect 1:100 ice jam flood levels if they are more severe than 1:100 open water flood levels or be based on a historical flood.

  • Flood inundation maps

    Flood inundation maps show areas at risk for different sized floods, including ice jam floods in some communities, and identify areas protected by flood berms. Because they map a wide range of floods, they are most often 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 likelihood maps

    Flood likelihood maps illustrate cumulative flood risks 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 show areas that are expected to be flooded and areas protected behind flood berms the same way.

  • Flood range maps

    Flood range maps compare 2 different sized floods and show what parts of a community can become at risk as flows change during a flood. Protected areas behind flood berms with residual risk are only shown for the larger flood being compared but they may also exist for the smaller flood.

View flood maps

The online Flood Awareness Map Application is the best way to view, interact with, and get more information about final and draft flood maps. The online flood map viewer includes 4 different types of flood maps, but the links below connect directly to draft and final flood hazard and flood inundation maps:

Switch between different types of flood maps by clicking on the buttons at the top of the screen, manually scroll and zoom to specific areas of interest, or use the search button on the left side of the screen to search for a specific location using a street address, postal code, latitude and longitude coordinates, or legal land description.

Location specific information, including river flow, flood zone, flow regime, water level and flood depth, are available by clicking on any part of a flooded area. When in the flood inundation and flood range map views, switch between smaller and larger floods using the slider on the right side of the screen.

The online flood map viewer also provides detailed information about individual flood studies and includes options to display Alberta Township System and cadastral overlays, use different backgrounds and print summary maps.

Flood map changes

A new approach to mapping floodways and updating flood hazard maps has been adopted in response to the concerns of Albertans and to provide flexibility in how communities across the province address flood hazards. The new approach better balances flood adaptation and resilience priorities and provides expanded flood hazard information to enhance public safety and inform local decision-making.

Contact

Connect with the provincial Flood Hazard Identification Program:

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