Fish Habitat Enhancement Structures
The placement of physical structures into rivers or streams to create pools, to alter channel morphology, and to provide cover and habitat for fish and other aquatic organisms has a long history. It was one of the first methods used to mitigate habitat degradation and to increase fish production in streams and rivers and also is one of the most common and widespread methods in use. Many different configurations of instream structures and methods have been used over the years to improve fish habitat. These techniques involve placement of materials such as large woody debris, boulders, and other materials into the active stream channel or actual manipulation of the active channel itself in an effort to improve fish habitat. They can be categorized by purpose (e.g. create pools, trap gravel) and material and can include such structures as boulder or log weirs, dams and deflectors, cover structures, rootwads and brush bundles, gabions, logjams and placement of spawning gravel. Because these activities seek to enhance habitat rather than restore a deficient process (e.g. riparian, hydrology) or return a stream to some pre-disturbance state, they are called instream habitat enhancement rather than restoration.
Water Resource Projects WaterResourcesEng@KleinschmidtGroup.com