What is flood mapping?
Flood mapping is a way to illustrate where flooding could take place and helps a community know more about where construction can happen and to what specifications. (This is technically referred to as a "Flood Construction Level" and means things such as the height of living areas in homes to ensure being above potential flood levels.)
History
From the McElhanney summary report:
Kitimat is no stranger to flooding. As part of the project, a review was undertaken of the records of historical flooding, dating back to 1913. A detailed list of all flooding records is provided in the main report and common areas of flooding are Radley Park, Hirsch Creek Park, the Service Centre, the Kildala area of town and the sewage treatment facility. Many of the flooding events that have occurred are as a result of rain on snow and debris slides. The impacts of these floods have included washing out of power lines and roads, property damage, and vehicles washed into the river, as well as initiating rescue efforts for residents and visitors to the town.
Flood risks and terminology
Understanding flood risks and terminology
You will often hear terms such as "20-year flood event", "100-year flood event" and so on. When you hear that, it doesn't mean that a flood would only happen every 20 or 100 years. For example, a 200-year flood event means there is a 1 in 200 chance of that level of flood happening in any given year, or a probability of half a per cent.
What is the District doing?
The District of Kitimat will be looking ahead at feasibility and plans to extend the lower dike. Extending the dike would provide additional protections to the community. This would be a long-term project given project considerations, and the required collaboration with Haisla Nation.
We estimate the plan to extend the dike will be ready by 2026.
The District will be updating our Official Community Plan and our zoning bylaws to address the risk of flooding in the community as well.
What we found by area
Mapping and study conducted by McElhanney has projected the 200-year flood hazard in areas of the community. Those images are shown below.
The modelling included in this section is based on bathymetric surveys that does not consider creeks or the District’s storm water systems, and show potential street-level impacts but not the impacts for specific properties
Cable Car
Cable Car is located on a bench on the broader floodplain and water levels are not able to reach the elevated area. No flooding was observed in the Cable Car area.
Service Centre
The model took into account the District flood operational plan which involves infilling the forest service road leading north from the Service Area and rail line through the dike. Under this condition the majority of the Service Area does not flood with the exception of minor inundation of low-lying pockets of ground at the southern terminus of the dike. Although the model covers the geographical area of Goose Creek, it should be noted that the study did not include the modelling of the creek itself, rather the impacts of the Kitimat River on the creek.
Kitimat townsite
All water enters the townsite around the southern end of the dike via Sumgas Creek. The flood hazard is considered low in this area meaning the water is forming shallow pools or flowing at a slow velocity. Higher hazard areas exist in depressions or channels where water will be deepest and fastest.
Kitamaat 1
The majority of the area is located on the floodplain. The hazard is considered extreme for this area.
Jugwees 5
The hazard is directly related to water depth and increases as the ground gets lower toward the waterline. The flooding extents will better inform development activities.
What to do when flooding ends
When a flood finishes, your work is not done.
- Be aware of hidden dangers in remaining flood waters; this can even include raised inspection chamber covers (i.e., manholes)
- Clean up only when it is safe, as the water could contain harmful contaminants and cause mold. Wear gloves, boots and a mask
- Structures could be damaged, stay out of your home or other property if you're in doubt of the safety
- If you rent your home, contact your landlord
- Compile information for your insurance such as photos of any damage
- Do not turn on electricity unless your electrical has been inspected by a qualified person
- If you are using a pump to remove water, place your generator outside and in a well ventilated area; carbon monoxide can be fatal when not properly mitigated
