Section 404 of the Clean Water Act authorizes the Secretary of the Army to issue permits for the discharge of dredged or fill material into streams, wetlands, and other waters. Applicants for Section 404 permits generally must mitigate for unavoidable impacts to streams and wetlands associated with their development. Stream mitigation may include such on-the-ground activities as preservation or restoration of vegetated riparian buffers; fencing of livestock from riparian buffers; stream bank stabilization activities; installation of in-stream habitat structures; and reshaping of streams to make them more stable and less likely to erode.
READ MORE at:  http://www.etowahriver.org/stream%20mitigation.pdf