Stream restoration

Stream restoration or river restoration, sometimes called river reclamation in the UK, describes a set of activities that help improve the environmental health of a river or stream. These activities aim to restore the natural state and functioning of the river system in support of biodiversity, recreation, flood management and landscape development.

Improved health may be indicated by expanded habitat for diverse species (e.g. fish, aquatic insects, other wildlife) and reduced stream bank erosion. Enhancements may also include improved water quality (i.e. reduction of pollutant levels and increase of dissolved oxygen levels) and achieving a self-sustaining, functional flow regime in the stream system that does not require periodic human intervention, such as dredging or construction of flood control structures. Stream restoration projects can also yield increased property values in adjacent areas.

Stream restoration differs from:

Restoration activities may range from a simple removal of a disturbance which inhibits natural stream function (e.g. repairing or replacing a culvert, or removing barriers to fish such as weirs), to stabilization of stream banks, to more active intervention such as installation of stormwater management facilities, such as riparian zone restoration and constructed wetlands. The use of recycled water to augment streamflows that have been depleted as a result of human activities can also be considered a form of stream restoration

Successful restoration projects begin with careful study of the stream system, including the historical weather patterns, stream hydraulics, sediment transport patterns and related conditions. Researchers evaluating restoration projects have found that many of these projects subsequently fail (e.g., with flooding or excessive erosion) because the projects were not designed with a sufficient scientific basis; restoration techniques may have been selected for aesthetic reasons.

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