Flood Plain Development

Definitions

• Design Flood

  The current design standard in Alberta is the one percent flood, defined as a flood whose magnitude has a one percent chance of being equaled or exceeded in any year. Although it can be referred to as a 100-year flood, this does not mean that it will only occur once every hundred years.

• Design Flood Levels

  Modeled water elevations within a flood hazard area based on design flood (one percent flood event). Design flood levels do not change as a result of development or obstruction of flows within the flood fringe.

• 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.

• Flood Hazard Area

  The flood hazard area is typically divided into floodway and flood fringe zones and may also include areas of overland flow.

• 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 discouraged in the floodway.

• Overland Flow (Flood Fringe)

  Areas of overland flow are part of the flood hazard area outside of the floodway, and are typically considered special areas of the flood fringe.

• More Information

  If you require more information, please contact Planning Services at the number at the bottom of the page or submit an online inquiry:

  Contact Planning