Floodplain ​& Dikes

The City of Coquitlam is currently fronting four major rivers, Brunette, Coquitlam, Pitt and Fraser River. In 2014 the City developed a Floodplain map outlining the areas which would be affected in the event of a flood. Kerr Wood Leidel (KWL) was hired to analyze the year 2014, 2100 and 2200 flood events and took into account climate change; the links below show the floodplain maps that were generated with the year 2200 inundation extent. A table is also included, which provides stationing (location) and flood elevations for the 2014, 2100 and 2200 flood event inclusive of freeboard.

The Fraser River flood level is established based on the historic 1894 flood levels, which saw flows of nearly 19,000 m3/s in the District of Mission. The Pitt River is connected to the Fraser River; and its flood elevations near the confluence of the two rivers are established from the Fraser River flood levels as follows:

  • 2014- 4.92m Geodetic
  • 2100- 5.84m Geodetic
  • 2200- 7.15m Geodetic

The Coquitlam River Flood Levels were designed based on the design 200 year flood, which is a flood that can occur on average once every 200 years.

Freeboard

As per the City’s bylaw, freeboard is the vertical distance added to the design Flood Level, to establish the Flood Construction Level (FCL). Provincially freeboard is the either 0.3m above the instantaneous 200 year peak water level or 0.6m above the daily 200 year peak water level.

Climate Change

Climate change can affect both peak sea levels and peak flows in watercourses. The current estimation for Sea Level Rise (SLR) is 1m by 2100 and 2m by 2200. The City’s floodplain maps take into account the projected sea level rise.

Dikes

Dikes protect land from inundation in the event the river level rises. Coquitlam has several dikes surrounding low lying properties, the properties protected by the dikes require pumps stations, which take the water from the lower lands and pump it into the river when the levels are high. The link below shows the location of the City’s pump stations as well as their dikes.

Engineering ​& Public Works Customer Service
604-927-3500
epw@coquitlam.ca