Division of Water Pollution Control

A Landowner's Guide to
Streambank Protection and Stabilization

By Wendy Smith, Melanie Catania and Dan Eagar
Artwork by Geralda Shockey

Frequently Asked Questions || Stabilizing Streambanks || Keeping Streams Healthy || Permits

Stabilizing Streambanks

Streams change as they mature. And streams, like the plants and animals that live near them, must adjust to the changes in the landscape around them. Some of the impacts that can affect a stream are: trees that have fallen into the stream can cause the stream channel to change course the removal of shrubs and trees along the streambank which can cause streambanks to collapse brush and scrub timber pushed into the stream from a logging operation or development project which can cause streambank erosion increased paving and roofing in the watershed, which can increase the runoff rate causing flooding and streambank erosion downstream

Many landowners in Tennessee lose valuable streamside property to erosion. Fortunately there are many ways to solve streambank erosion problems. This brochure gives an overview of some of the solutions. For your particular stream, please contact your district conservationist or the TDEC Environmental Assistance Center near you. Phone numbers are provided on the back page.

Keeping Streams Healthy

Contour farming helps keep the soil on the land and out of the stream. Landowners can minimize flooding damage by allowing trees and shrubs to grow naturally along streambanks. Streams are naturally curvy. These curves, or meanders, help slow down the flow of water and reduce its force, which helps minimize erosion. If a stream has been unaturally straightened, it often will erode its banks and reestablish curves. Fencing cattle out of streams, or providing them with only one access point, helps keep both the cattle and the water healthy. A simple solar pump, tanks, ponds and other contained sources can provide fresh water to livestock away from the stream. Healthy, natural streams move sediment, which includes gravel, and deposit it as "pointbars" or gravel bars in the bends of streams. These pointbars slow the water down, decreasing the damage caused by flooding.

Seven Ways to Prevent Streambank Erosion

Keep vehicles and equipment out of the stream whenever possible Keep trees and plants along streambanks Remove fallen logs and other woody debris from the stream channel by winching or dragging as soon as possible Provide a water source such as a pond or tank for livestock away from stream or provide controlled access to the stream at a stable location Allow your stream to establish a natural path and slope whenever possible Use anchored trees, rootwads, large rocks, plants and other natural materials to repair eroding banks Conduct ongoing maintenance to keep small problems from becoming big problems!

One successful method of streambank stabilization is known as bioengineering. Bioengineering uses natural materials such as trees, roots and logs to divert water away from a streambank and stabilize the bank. This drawing illustrates a cedar tree revetment project which uses live cedar trees anchored to the base or toe of the bank. Cedars are bushy and slow to rot. As sediment collects in their branches, they provide a natural seedbed for streamside trees such as willows and sycamores to take root and grow.

Over time this revetment is stabilized by the growing root systems of the willows and sycamores and the streambank is restored.

A simple method to hasten the establishment of stream bank protection is to use live willow stakes cut during winter.

Other bioengineering methods include the use of rootwads from downed trees or limited use of large rock to deflect fast-moving water from erodible banks.

When unstable streambanks become vertical or undercut, they can be reshaped to a more gentle slope and stabilized with grasses and other vegetation. Most bioengineering methods must be adapted to site-specific circumstances. Before undertaking projects, landowners should contact NRCS or other sources for technical assistance.

How Much Does Streambank Stabilization Cost?

Cost Comparison and bank heights for different streambank stabilization methods*

 

100 linear feet of excavation, cedar tree revetments and native plantings
4 feet high $788.00	8 feet high $1,135.00	12 feet high $1,695.00

 

100 linear feet of excavation, rootwads and native plantings
4 feet high $550.00	8 feet high $945.00	12 feet high $1,570.00

 

100 linear feet of excavation and rock riprap to top of bank
4 feet high $3,670.00	8 feet high $6,310.00	12 feet high $9,150.00

 

100 linear feet of excavation and rock riprap to 1/2 of bank height and native plantings to rest of the way up the bank
4 feet high $2,570.00	8 feet high $4,050.00	12 feet high $5,775.00

Note: Keeping trees and shrubs on the streambank and keeping livestock out of the stream will help the long-term stability of these structures.

*These cost-estimates prepared by: Terry Horne, Bio-Environmental Engineer, USDA-NRCS

Frequently Asked Questions || Stabilizing Streambanks || Keeping Streams Healthy || Permits