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Flood mapping types and process

Developing flood maps is complex and time consuming. Explore this page to learn more about:

Looking for a flood map? Explore free ready-to-use maps to deepen your understanding of flooding. You can also access the flood mapping resources in your province or territory.

Looking for data? Explore our data related to flood mapping.

Flood mapping process

The creation of a flood hazard/risk map requires several steps and the expertise of many people. Steps in flood map creation range from community engagement and data acquisition to producing the map. The diagram below demonstrates the different steps of the process to create a flood map.

For guidance on each of these steps, visit the Federal Flood Mapping Guidelines Series.

Circular diagram demonstrating the steps for federal flood mapping. Engagement and collaboration are at the center and in each step.

  • Priority Setting

    Identify and prioritize areas at high risk of flooding that require up-to-date flood maps.

  • Data Acquisition

    Gather information such as meteorological, historical and land elevation data, to help predict where the water will flow in case of flooding. This information will be used for hydrologic and hydraulic modelling.

  • Hazard Assessment

    Analyze historic precipitation and flow data to understand future floods. Consider climate change, meteorology and other factors that contribute to potential flooding.

  • Modelling and Mapping

    Delineate flood levels and predict flooding scenarios by running hydrologic and hydraulic models based on acquired data. Hydrologic modelling estimates a range of potential flood flows, and hydraulic modelling calculates water levels along rivers for those flows.

  • Communication and Dissemination

    Produce and disseminate maps based on modelling for easier interpretation.

  • Risk assessment

    Use maps and other information to identify flood risk zones.

  • Mitigation

    Implement land-use restrictions and invest in measures to reduce impacts of flooding.

  • Engagement and Collaboration

    Inform and gather feedback from community members and stakeholders throughout entire process.

Types of flood maps

Flood maps identify the areas covered by water during real or potential flood events. They can identify the probability of floods and its impact on structures, people, and assets.

Under the broad definition of “flood map”, different types of geospatial, hydraulic, and hydrologic information can be presented to meet specific assessment requirements. The following different types of flood maps are used in Canada:

City map showing the extent of flood zones and graduated colors representing the frequency of storm events.

Inundation Maps

Show the floodwater extent of real or potential flood events. They are used to inform emergency preparedness plans for communities in flood zones and flood hazard zones. (Image source: Toronto and Region Conservation Authority)

Map showing natural and man-made features. Along the river, a section is colored to show the extent of the water in the streets and around the houses during a flood.

Flood Hazard Maps

Show the results of hydrologic and hydraulic investigations, including areas of potential flooding in different scenarios. Flood hazard maps are engineering maps, often used as regulatory maps for land use planning related to flood mitigation. (Image source: City of Fernie)

City map with a graduated colour grid where the lightest color represents a very low flood risk to the darkest representing a very high flood risk.

Flood Risk Maps

Demonstrate potential adverse consequences (such as social, economic, environmental or cultural) that communities may face during a flood scenario.(Image source: District of Tofino [Murphy et al., 2020])

City map with graduated colour representing likelihood of flooding and the extent of the water. The lightest color represents a lower likelihood of flooding and the darkest higher likelihood of flood.

Flood Awareness Maps

Communication maps that provide more context alongside flood hazard/risk maps. They may show the history of flooding in their communities, or potential for future flooding. (Image source: City of Calgary)

 

More details on the requirements for various types of flood maps as well as guidelines for the associated digital geospatial data are available in the Federal Geomatics Guidelines for Flood Mapping.

Science of flood mapping

The Government of Canada is dedicated to science and research that can support and advance flood mapping and risk assessment. Learn more about the science of flood mapping.

For more information:

 

Find out more

Reach out to us

For more information, please email geoinfo@nrcan-rncan.gc.ca

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