Habitat restoration projects address both the in-stream
habitat and riparian area of a watercourse. Habitat restoration creates a greater diversity of habitat for native aquatic species, in all their life stages.
In-stream habitat devices, such as digger logs, and deflectors, restore more natural stream flow dynamics. They are spaced and placed in a stream or river with consideration given to the watershed area above, annual rainfall, and natural and artificial features of the stream. When properly designed and built, habitat restoration structures will restore the pool and riffle sequence of the stream, sort the substrate, and clean sand and silt out of gravel beds. Over time, the stream channel is deepened and narrowed.
Repairing and restoring the stream banks and re-establishing riparian vegetation are also important aspects of improving fish habitat. Stable stream banks reduce erosion and protect riparian areas which provide shade, resulting in cooler temperatures, overhead cover from predators, food and nutrients from falling leaves, insects and other organic matter to the fish and aquatic insects. Other restoration efforts include increasing cover in-stream with half logs, removing blockages and constructing fishways.
Many habitat problems can be addressed using techniques currently available. Before deciding on the approach some investigation is needed to determine the limiting factors to fish populations in an area. Restoring a stream will involve not only work in and near the stream but also discovering the source of the problem and working with others in the watershed to find solutions.