Question: Can vegetation hold the slope?
Thick healthy vegetation contributes greatly to slope stability by holding
soil in place with its root system. Even oversteepened banks can be held
in place by existing vegetation. Once vegetation is cut or removed from
oversteepened banks, revegetation may be very difficult to do without
some regrading and/or stabilization with a structural alternative such
- Maintain as much of the naturally occurring vegetation on the banks,
- Remove all dead vegetation and debris which may kill vegetation by
- Where there is no vegetation or regrading is necessary, select the
best vegetation for the site, plant it, protect it and foster its growth
until it is well-established.
- For sites where vegetation alone has been unsuccessful in stabilizing
a slope, install some combination of rip-rap and vegetation
- Keep foot traffic to a minimum around eroding slopes and revegetated
areas. Stable foot paths or constructed walkways work well to achieve
Question:Should I use vegetation alone or with rip-rap?
There are many factors which will determine if plantings alone will be
successful in stabilizing a bank. In addition, these factors will also
determine what combination of vegetation and rip-rap should be applied
to any given shoreline.
Before investing your time and money, evaluate the site (or consult with
a professional) for the following factors:
- Existing vegetation - The presence of native vegetation
below the toe of slope is a favorable indication that further plantings
will be successful.
- Fetch: How many miles of open water does wind blow across
before reaching your property? This distance, and the dominant direction
from which it blows is important in designing a project. If fetch
is greater than 5 miles, it is unlikely vegetation alone will successfully
halt erosion. Vegetation alone is most successful where the fetch
is less than half a mile.
- Shape of shoreline: Orientation of the shoreline helps
to determine what the forces of erosion are, and whether vegetation
alone (such as in protected coves or lagoons) or some combination
of vegetation and rip-rap will work to halt erosion.
- Boat traffic: The numbers of boats and how close they travel
to a shoreline will help to determine the choice of a solution for
a given site.
- Width of beach above mean high tide: Beaches which are
greater than 10 feet above the mean high tide, or which can be regraded
to create 10 feet in width above the mean high tide line have the
best chance for successful vegetation growth.