Announcements / Science

Shoring Up! Stabilizing Your Lake Shoreline

After a long winter of ice push followed by high water and waves in the spring, you may be wondering how to best approach your eroded lake shoreline or crumbling retaining wall. While erosion is a natural process, an eroding shoreline can result from a combination of both upland runoff and in-lake ice and wave action, and the rate of erosion can be heavily influenced by our actions at and around the shoreline.

Stabilization projects that mimic the properties of a natural lake shoreline are the preferred approach to achieve long-term shoreline stability. To reduce erosion from upland run-off and further protect the shore, minimize the amount of lawn-to-lake landscaping by planting native trees, shrubs, and perennials along the shoreline. In addition to being well-adapted to the soils and local climate, native plants are the preferred food for the region’s wildlife and pollinator species. Planting native vegetation supports biodiversity, making the shoreline more resilient to aggressive invasive species.

Areas along the shore that need extra support can benefit from the addition of natural materials including stone, fiber coir rolls, and biodegradable landscaping fabric. Dry-laid stone and rip rap provide solid reinforcement against ice and wave action, while still allowing runoff from further upland to infiltrate. Biodegradable filter fabric and a layer of clean crushed gravel placed behind the rock will help prevent further loss of sediment from the bank. Vegetation planted among the rocks and at the top of the bank will greatly increase the long-term stability of the shoreline while providing wildlife habitat.

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A heavily eroded shoreline on Lake Bomoseen is afforded some protection with rip rap, biodegradable soil lifts, and new native plantings. The yellow turbidity curtain ensures sediment and debris do not leave the immediate project site.

Solid vertical walls are “hardscapes.” Whether they are concrete, railroad timbers, or gabion baskets, these walls create a sterile disconnect between the water and upland areas, which reduces the value of shoreline habitat and impedes access for species that require connectivity between the land and water. Vertical retaining walls are mistakenly perceived to be more stable than the other methods described above. However, retaining walls do not absorb incoming wave energy. Instead, waves reflect off the hard surface, resulting in scouring and erosion elsewhere around the wall, undermining the integrity of the wall at the water’s edge and along its sides. Retaining walls are costly to install and have a high failure rate over time. For these reasons, new retaining walls are generally not approved.

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Swapping grass lawn for some native vegetation and replacing the vertical retaining wall with a slope of boulders or dry-laid stone would greatly benefit this shoreland.

Do I need a permit for my shoreline stabilization project?

You got a permit, now review the conditions!

YOU, the permittee, are responsible for understanding and following your permit. Here are some common permit conditions associated with shoreline stabilization projects:

  • Wait until July 1: Spring is a crucial season for fish and aquatic wildlife that use the immediate shoreline area (littoral zone) for spawning and nesting. Most Lake Encroachment permits carry a standard condition that work below mean water level not begin until July 1 of the calendar year.
  • Minimize the mess: Turbidity curtains and/or silt fences around the work site are required prior to starting the project. A secure curtain must be maintained throughout the project to contain turbidity and minimize impacts to water quality elsewhere in the lake.
  • Leave the “natural stuff”: A permit to replace a failing retaining wall is not permission to alter the lakebed or remove vegetation at the shoreline unless explicitly approved to do so in a permit. A Lake Encroachment permit requires that all rocks, boulders, and large woody debris present in the lake be left in place and not removed.
  • Follow your approved application: Think you may need to alter your plans after receiving a permit? Any proposed changes or deviations to the approved plan will require additional review by your regional Lake and Shoreland Permit analyst and potentially a permit amendment.

Unsure of how to proceed with a project? Wondering what your permit says? Get in touch with your regional Lake and Shoreland Permit analyst.