Introduction:
Streambank erosion is a continually occurring natural condition that can be greatly accelerated by human activity. Over time, natural streams tend to reach equilibrium so that erosion at one location is roughly balanced by deposition at another. Human alterations to hydrologic and stream flow patterns can, however, upset this balance and lead to severe consequences. Streambank failure, defined as the collapse or slippage of a large mass of bank material into the stream, is one example of what happens when this balance is upset.

Because of the complexity of physical processes affecting streams, there is not one single type of streambank failure, but many types. Consequently, streambank protection or restoration practices must be tailored to the specific causes of the streambank problem. Through an understanding of the problem's cause and selection of the proper bank protection method, the likelihood of protecting an eroding streambank is significantly increased.

Rock Riprap
One of the most common techniques used for streambank protection is rock riprap. It is a very effective method when used properly, but also expensive. Riprap consists of rock material placed on the bank surface at the location of the erosion problem to protect the bank from stream erosive forces. The rock should extend far enough up on the bank to where natural vegetation can provide adequate protection. MN Department of Transportation and Natural Resources Conservation Service both have specifications for streambank restoration projects.

Bioengineering
This represents an attractive alternative to the use of rock riprap for streambank protection. This approach combines mechanical, biological, and ecological concepts to arrest and prevent shallow slope failures and erosion. Immediate soil reinforcement is achieved by specific plant arrangements at the site. In conjunction with the vegetative cover, structures should also be used. Structures stabilize slopes during the critical time for seed germination and root growth. A well-established root zone will provide sheer strength and resistance to sliding. Overall benefits of bioengineering practices include slope stabilization, improved infiltration, runoff filtration, excess moisture transpiration, ground temperature moderation, habitat improvement, and aesthetic enhancement.

Bioengineering techniques can be used to develop sustainable systems for slope or streambank protection. The combination of correct assessments of stream corridors along with bioengineering practices has proven to be cost effective and environmentally sound. Installations can be labor intensive, but less costly than conventional engineering.

Appropriate Bioengineering Streambank Protection Measures:
* Head cutting and general bed degradation - Bioengineering not recommended / Grade control or bed armoring needed

* Toe erosion and upper bank failure - Live cribwall, Brushmattress, Rock toe with vegetation, and Joint plantings

* Local bank scouring - Branchpacking, Live cribwall, Live fascine, Joint planting, Tree revetment, and Rock toe with vegetation

* General scour of middle and upper bank - Brushmattress, Live fascine, Live stakes, and Joint plantings

* Gully from overbank runoff - Divert runoff and repair area with Branchpacking, Live Fascine, Live Stakes and Drop pipes and structures

*Piping - Divert runoff and repair area with Branchpacking and Live staking

Another method for large sections of streambank protection is the installation of hook rock veins. This method involves constructing "j" hooks of rocks angled into the stream to make the water run "uphill" to reduce velocity and move the flow away from the bank back to the center of the channel.