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Lower Mainland
Flood Management Strategy Maps

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Fraser River Freshet (Spring) Flood Scenarios – Present Day

The five maps below show flood depths and extents for Fraser River freshet floods of increasing magnitudes based on the historical record and today’s climate (present-day conditions).

  • 1894 freshet flood event. [Map PDF] [Animation] The 1894 Fraser River flood is considered to be slightly more severe than the estimated 0.2% AEP flood today. The 1894 flood is considered the “design flood” to inform dike design and construction along the lower Fraser River dikes.

Fraser River Freshet (Spring) Flood Scenarios – Year 2050 with Climate Change

The two maps below estimate flood levels under projected climate change conditions in 2050. The conditions include 0.5-metre sea-level rise and changes in peak river flows. A 1% AEP flood in 2050 will be more severe than a 1% AEP flood today. Similarly, a 0.5% AEP flood is projected to be more severe in 2050 than today.

Fraser River Freshet (Spring) Flood Scenarios – Year 2100 with Climate Change

The three maps below estimate flood levels under projected climate change conditions in 2100. The conditions include 1-metre sea-level rise and changes in peak river flows. A 1% AEP flood in 2100 will be more severe than a 1% AEP flood today.

Coastal Storm Surge (Winter) Flood Scenarios within the Fraser River Flood Hazard Area – Present Day 

These two maps show the effects of a coastal storm–caused flood within the Fraser River flood hazard area only. These maps exclude flood hazard areas in the Lower Mainland outside of the Fraser River flood hazard area, such as Boundary Bay, Burrard Inlet, Lions Bay, and Squamish.

Coastal Storm Surge Flood Scenarios – Present Day and with Sea-Level Rise

The two maps produced for these coastal flood scenarios are based on a simplified approach through extending the estimated ocean flood level across the land. The 2D model was not used for these maps. They assume there are no dikes and do not consider localized wind and wave effects, subsidence/uplift, or the tidal cycle. In some cases, more accurate, detailed modelling and mapping may be available from municipalities.

  • 0.2% AEP coastal storm surge flood with current sea level. [Map PDF]
  • 0.2% AEP coastal storm surge flood with 1m sea-level rise. [Map PDF]

Dike Breach Maps

Dike breaches were simulated as part of the Lower Fraser River 2D flood modelling project for the Lower Mainland Flood Management Strategy to develop an understanding of potential flood extents, flood progression, depths and hazard.

The simulations show how severe a flood scenario can be, how quickly it can occur, and why it is important to evacuate early, before a potential dike breach. For emergency planners, it is helpful to see the timing and extent of flooding, water velocity, and flow direction and progression when developing emergency plans. The simulations show that flooding from a dike breach can progress quickly, cutting off evacuation routes and reaching residents, livestock and/or infrastructure within a few hours.

The dike breach locations were selected to provide a range of results, not necessarily because they are more likely to breach. The locations were selected based on criteria including: the breach is capable of being modelled and may create significant local or regional impacts. The breaches are hypothetical and modelled for learning purposes only. Please refer to the notes on each map for more information.

For the following maps, the flood scenario modelled is the 1894 freshet flood event, unless otherwise stated.

  1. Vedder Canal [Map PDF]
  2. Upstream Kent [Map PDF]
  3. Upstream Chilliwack [Map PDF]
  4. Upstream Pitt Meadows [Map PDF]
  5. Queensborough [Map PDF]
  6. Upstream Delta (0.2% AEP freshet flood with 1m sea-level rise) [Map PDF]
  7. Chilliwack and Vedder Canal [Map PDF]
  8. Kent, Chilliwack, Vedder, and Matsqui (0.5% AEP freshet flood) [Map PDF]

Lower Mainland Flood and Environment Atlas

The Lower Mainland Flood and Environment Atlas was developed as part of the Lower Mainland Flood Management Strategy. This atlas contains flood extents for the Lower Mainland for select flood scenarios along with a range of environmental values and features along the lower Fraser River and coastal foreshore areas. The atlas is a resource when decision makers are considering potential environmental benefits (and adverse impacts) of floods as well as flood risk reduction projects or policies. The flood levels shown on this portal are based on the 2015 Analysis of Flood Scenarios and mapping from the 2016 Lower Mainland Flood Vulnerability Assessment.

The following maps are overview maps of flood extents referenced in the Phase 1 Summary Report (2016). Please refer to the report for context.

Coastal Flood Scenarios (A and B) Overview Map

Fraser River Flood Scenarios (C and D) Overview Map)

In 2015, an assessment of flood vulnerability was developed for the Lower Mainland Flood Management Strategy initiative. Flood vulnerability and risk maps were produced to show coastal and Fraser River flood extents in relation to select critical infrastructure and facilities, including emergency operations centres, hospitals, schools and airports.

The regional and subregional maps below  are extracted from the Regional Assessment of Flood Vulnerability report. Please refer to the report for details.

Coastal Flood Scenarios Subregional Maps
All Regions | Region 1 | Region 2 | Region 3 | Region 4 | Region 5

Fraser River Flood Scenarios Subregional Maps