Renovate your retaining wall

In the continuing quest to maintain a neat and tidy shoreline, many waterfront owners remove important shoreline vegetation, which inevitably leads to the problem of erosion eating away at their property.

Many people then install a retaining wall.

Retaining walls have long been a fixture on many shorelines in B.C., especially Lake Windermere. The misguided belief is that the wall will solve the erosion problems, while creating more space for lawn. What many property owners don’t realize is that the construction and maintenance of a retaining wall on their shoreline wrecks havoc on the lake’s biological processes and aquatic life. Retaining walls can actually contribute to shoreline erosion and can make problems worse over time. They interfere with natural lake processes by altering currents along the shoreline, causing waves to slam against the vertical wall.

Not only do retaining walls affect natural processes and currents, but they also affect lake life. “Hardened” shorelines, such as retaining walls, degrade water quality, destroy fish and wildlife habitat, and block wildlife access to and from the water.

If riparian vegetation exists on site, it must be protected. The removal of such vegetation within 15-30m of the high water mark is unlawful. According to Section 35(1) of the federal Fisheries Act, “No person shall carry on any work or undertaking that results in the harmful alteration, disruption or destruction of fish habitat.” If shoreline vegetation exists then erosion usually isn’t a problem and a retaining wall isn’t required.

However, even if you currently have a retaining wall on your shoreline, all is not lost. There are a few things you can do to reduce the pounding your retaining wall will take and improve wildlife habitat along the shore.

• Restore or plant a strip of deep-rooted native vegetation along the retaining wall. This will help filter runoff before it reaches the water and will reduce the risk of erosion occurring and gullies forming behind your wall since the plant roots act to hold the soil together.

• Plant overhanging native shrubs to help provide shade and keep the water cool. Leaves and woody debris that fall into the water also provide food for species at the base of the food chain.

• Drill planting holes into the retaining wall and plant cuttings or plugs of overhanging plants and vines in them.

• If you have riprap (large, loose stones) along your shoreline, plant shrubs in open spaces among the rocks.

By following these simple steps, you can transform a barren, hardened shoreline back into a productive habitat that controls erosion and provides wildlife habitat.

For more information, contact the Lake Windermere Project at 250-341-6898. You can also visit us in the old District of Invermere office beside the Invermere Community Centre.

The Lake Windermere Project is a long-term comprehensive stewardship program dedicated to safeguarding the health of our lake. The Lake Windermere Project is made possible by generous support from Wildsight, Environment Canada, the District of Invermere, Columbia Basin Trust, the Real Estate Foundation of B.C., and those community members who have donated through the Lake Windermere Ambassadors program.

Information provided by the Department of Fisheries and Oceans and the Muskoka Watershed Council.