GNWT Releases New Flood Maps and Community Planning Guide

The Government of the Northwest Territories (GNWT) is releasing new flood hazard and flood inundation maps for five of the ten communities at highest risk of river flooding in the Northwest Territories (NWT). Informed by community input, the latest available information on flood hazard areas, and the impacts of climate change, the new flood maps replace existing maps that were completed in the 1980s.

New flood hazard and flood inundation maps are available for Aklavik, Fort Simpson, Hay River, Kátł’odeeche First Nation and Nahanni Butte. Flood maps for Fort Good Hope, Fort Liard, Fort McPherson, Jean Marie River and Tulita will be available by 2028. This work is primarily funded by the Government of Canada’s Flood Hazard Identification and Mapping Program.

The new flood hazard maps show a 200-year flood, meaning there is a 1 in 200 (or 0.5%) chance a community will flood in any given year. Existing maps for NWT communities, developed in the 1980s, show either a 100-year flood (a 1% chance) or the largest known historical flood at that time. The new maps were informed by detailed engineering studies and longer, more comprehensive data, allowing for an updated assessment of flood hazards and higher-magnitude events.

To accompany the new maps, the GNWT developed the Planning in Flood Hazard Areas Guide under the NWT Community Planning Framework. This guide provides policy and technical guidance to support community governments with integrating new flood hazard maps into community planning and development decisions. Using the 200-year flood hazard map aligns the GNWT’s approach with the federal government’s guidance for disaster assistance funding eligibility, reflecting an increased flood risk associated with climate change across the country.

The flood maps and community planning guide are part of a multi-departmental effort between the Department of Environment and Climate Change, the Department of Municipal and Community Affairs, and the Department of Finance’s NWT Centre for Geomatics. Collaborating and engaging with community and Indigenous governments has been critical in developing the flood maps.

Quotes:

“The new flood hazard and flood inundation maps and community planning guide are important tools to support community emergency management plans and land use planning. The maps will guide flood mitigation activities, improve public safety, and empower residents and property owners to make informed decisions about their flood risks. The maps will also assist community governments in adopting best practices for community development and land use planning and will help the NWT better align with Public Safety Canada disaster assistance requirements.”

- Vince McKay, Minister of Municipal and Community Affairs

“Flooding is becoming more frequent and severe across the Northwest Territories, and communities need reliable, current information to prepare and adapt. The new flood maps combine the best available science with Traditional and local knowledge, ensuring they reflect the realities facing communities today. These tools are a key part of the GNWT’s work to support community hazard mapping and strengthen local planning. By equipping communities with practical, accessible information, we are helping reduce risk, protecting people and infrastructure, and building a more resilient territory that is ready for emergencies.”

- Jay Macdonald, Minister of Environment and Climate Change

Quick facts

Riverine flooding occurs when water flows outside of a river, stream, or creek channel and onto normally dry land. Causes may include ice jams, heavy rainfall and snowmelt. It is often referred to as fluvial flooding.
Flood hazard maps for the NWT typically account for ice jams, the most common cause of flooding in the territory. For Nahanni Butte, the flood hazard maps account for open water flooding.
Current, accessible, high-quality flood mapping helps governments, communities, and individuals understand flood hazards and implement effective planning and mitigation strategies.
New flood hazard and inundation maps are available for Aklavik, Fort Simpson, Hay River, Kátł’odeeche First Nation and Nahanni Butte. Flood maps for Fort Good Hope, Fort McPherson, Fort Liard, Jean Marie River and Tulita will be available by 2028.

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GNWT Releases New Flood Maps and Community Planning Guide