Steep Slope

Living Near Steep Slopes

Properties near natural slopes and ravines are desirable due to the unique scenery and close proximity to nature; however, steep slopes are susceptible to failure and can cause a landslide (downslope movement of material from gravity). While the risks of slope failures are usually low, homeowners should be aware of the risks and watch for any signs of slope failure. Slope failure and landslides are more likely to occur after extended periods of heavy rainfall; this causes the slopes to become saturated with water and compromises the strength and structure of the slope.

There are several factors that can affect your slope stability and realizing them can allow you to take proper care and decisions at the top of the slope. See below for examples of measures homeowners can do to protect their slopes.

  • Avoid placing fill (yard waste included) at the top of the slope or near drainage channels, including building retaining walls to raise your property.
  • Divert water away from the slope, including roof drainage. If water is draining to the ravine or slope, pipe it to the bottom of the slope to prevent saturating the slope.
  • Comply with City guidelines and bylaws as these are in place to protect homeowners. This includes avoiding placement of sheds, pools, decks or patio at the top of the slope and adding excessive weight.
  • Maintain vegetation of the slopes as this will strengthen slope stability. Exposed soils increase the chance of slope instability; plant native trees that are suited for this weather/climate.

Signs of Slope Failure

  • Soil separating (moving) from foundations or structures.
  • Cracks along your yard near the slope.
  • Leaning trees, retaining walls or fences
  • Increase in water levels at the bottom of the ravine (due to debris filling the channel bed)

In efforts to proactively manage risks of landslides the City conducts ravine inspections every year. Due to the very steep slopes in the Chines Escarpment a slope stability assessment was conducted in 2013. The assessment was a qualitative analysis based on interpretation of the topographic data and visual site observation by the consulting company Associated Engineering. A follow up detailed geotechnical investigation was later conducted by Golder Associates for properties along Corona Crescent both reports are available in the links below:

*Homeowners are responsible for managing and maintaining their lot, including steep slopes. If  you see signs of instability on your slope contact the City’s Engineering & Public Works department at 604-927-3500 or ​epw@coaquitlam.ca.

Related Resources

 

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