Preventing
Erosion Problems & Stream Bank Stabilization
Preserve native streamside vegetation.
Native riparian plants growing within a stream corridor provide
important habitat and help to
stabilize banks. In times of flooding a well-vegetated stream bank may
be your property’s best protection.
But beware! Invasive
non-native species can choke out native plants.
In some instances these plants can actually impede stream flow and
contribute to flooding. Invasive plants also have little or no habitat
value for wildlife. Yet mowing, clearing or stripping away non-native
vegetation can promote erosion. Seek professional advice before
removing invasive species, and replace with native vegetation as soon
as possible.
Avoid removing natural
debris.
Removing branches, boulders, and dead vegetation from a stream can harm
fish and wildlife. Natural debris provides food and cover for fish,
aquatic insects and other animals. However, if debris poses a serious
flooding or erosion hazard careful removal may be necessary. Seek
advice from appropriate agencies before removing debris (see back page
for phone numbers).
Check for erosion
regularly and correct problems promptly.
When flowing water meets unprotected soil, erosion almost always
results. Barren slopes on any portion of your property (not just stream
banks) can lead to sedimentation problems in the stream. Too much
sediment (soil, sand and fine gravel) fills in the streambed and
reduces its ability to carry floodwaters. Excessive sediment can also
destroy pools, eliminate shelter and fish spawning habitat, and
diminish food supplies for fish and aquatic insects.
Keep an eye on the bottom of the slope! A vegetated slope is the best
defense against under-cutting and slumping banks. Replant barren slopes
or disturbed soils as quickly as possible. On slopes that are not too
steep, a covering of straw over newly bared earth will prevent erosion
until vegetation can grow back. Putting tires or slabs of concrete over
the bank will usually create more erosion rather than lessen the
problem. See the next section for more effective techniques for
treating an unstable bank.
STABILIZING
STREAM BANKS
Streams are constantly
reshaping their channels
through natural processes, scouring outside curves and depositing
sediment inside bends in the waterway. A stream’s natural tendency to
meander can be aggravated by human activities throughout the watershed.
Increased volumes of stormwater runoff into streams, removal of natural
vegetation, and upstream alteration of the channel may lead to erosion
problems on banks that were once stable. Unstable banks can lead to
extensive bank failures and add large volumes of sediment to the
stream, resulting in property loss.
Tree
and plant roots reach into the soil and stabilize stream banks. This helps prevent erosion into the
stream, a major cause of turbid or murky water.
Streams are complex systems. Stabilizing banks requires knowledge and
expertise. Actions taken to protect your bank may have unforeseen
consequences downstream. You may unintentionally pass your erosion
problems to your neighbor. If you have a serious erosion problem,
consult with a qualified professional in bank stabilization and repair.
Check with one of the offices listed on the back page. You may
need to obtain a permit as well. Municipalities
can also have local stream ordinances with which you must comply.
Local, state
and federal permit processes help ensure riparian habitats and stream
flows are
protected, and that property owners do not inadvertently worsen the
situation.Remember, these agencies are
there to assist you!
Here
are a few bank
stabilization techniques
The
best erosion control is
proper stream care. Neighbors must cooperate in their efforts and share
responsibility for maintaining a healthy stream.
If
the native riparian
vegetation has been depleted or removed, but severe bank erosion has
not yet
occurred, you may be able to re-establish or add to the remaining
vegetation on
your own. Find out what types of native vegetation to use on your
particular
site and how to plant and care for them.
Modify
steep banks to
shallow or moderate slopes and revegetate with native riparian plants.
(Live
cuttings of willow driven into the bank or bundles of live cuttings
secured to
the banks can be effective).
Create
terraces and plant
with native species.
Retrofit
existing bank
stabilization with planting collars. Remember!
Erosion
control need not be costly.
Consider
low-tech, lower cost, stream
friendly alternatives first.
Virtually
any activity in a wetland requires
a permit. Be sure to seek
professional advice before taking action.
Diagram courtesy of
USDAForest Service and the Maryland Cooperative Extension, 2002