Living beside a coulee slope

Slope failures on coulee slopes are quite common in the Lethbridge area. These slope failures can sometimes be inconsequential but can also cause serious damage to infrastructure and private property depending on where they occur. Slope failures can occur for a variety of reasons but is mainly due to the underlying soils becoming saturated with water which then decreases the shearing strength, causing a mass of soil to slide down the slope. Developments adjacent to coulee slopes can create or exasperate failures due to the installation of roads, sidewalks, houses, and other structures that reduces the effectiveness of evapotranspiration and can create a perched water table.

Although some slope failures cannot be prevented, residents can take some measures that may help prevent or slow the progression of an existing failure. These measures can include:

• Directing concentrated drainage such as downspouts or sump pumps away from the slope
• Creating a sheet flow effect for drainage instead of concentrating to one location
• Installing a septic system as far away from the slope as possible, and having it inspected regularly
• Zeroscape, where the native vegetation is not disturbed and remains natural
• Xeriscape, where low water or drought tolerant plants that require no supplemental watering are planted

Any of these measures can help in preserving our coulee slopes.

View the video on the right to learn about preventative measures for slope failure.