Over time streams erode and change pattern to adapt to changing surroundings. Intense development increases paved surfaces which also increases the amount of runoff channeled to creeks and streams. The result is excessive erosion that leads to the collapse of stream banks and the deposition of silt downstream.

Stream restoration is the process by which a degraded stream is taken back to its natural state before development. If this is not possible, other steps may be taken to help the stream adjust to the urban environment. Soil bioengineering is a critical component of stream restoration.

This is a stream suffering from extreme erosion.

Three Levels of Stream Protection
To restore a stream means to re-create meanders, stabilize soil and install gently sloping stream banks. Stream restoration is not always possible due to constraints such as utility crossings, structures or roadways. To enhance a stream is to attempt meanders and gentle slopes where possible and to stabilize the soil. To stabilize a stream is simply to secure the stream banks from further erosion because constraints limit other degrees of stream protection.

Soil Bioengineering
Soil bioengineering is the specialized use of plant materials to stabilize soil by combining engineering principles with plant science. The roots of plants grow into the soil and bind the soil particles together thereby reducing erosion.

Bioengineering is more desirable than any type of "hard" stabilization like rip-rap (rocks) or concrete for many reasons:

1. Plants are self-correcting. They will grow into open pockets. Rip-rap will not move back onto a bare area of stream bank.
2. Plants are natural materials that provide habitat for aquatic life.
3. Plants are often cheaper to install.

Soil bioengineering utilizes live stakes for plant materials.