Salmon River by Steve Snyder gusssss@earthlink.net |
Why is Stream Corridor Restoration Important?
The United States has more than 3.5 million miles of rivers and streams
that,along with closely associated flood plain and upland areas, comprise corridors of
great economic, social, cultural, and environmental value. These corridors are complex
ecosystems which include the land, plants, animals, and network of streams within them.
They perform a number of ecological functions such as modulating stream flow, storing
water, removing harmful materials from water, and providing habitat for aquatic and
terrestrial plants and animals.
Stream corridors also have vegetation and soil characteristics distinctly different from surrounding uplands and support higher levels of species diversity, species densities, and rates of biological productivity than most other landscape elements. Streams and stream corridors evolve in concert with and in response to surrounding ecosystems.
Changes within a surrounding ecosystem (e.g., watershed) will impact the physical,
chemical, and biological processes occurring within a stream corridor. Stream systems
normally function within natural ranges of flow, sediment movement, temperature, and other variables, in what is termed "dynamic equilibrium." When changes in these variables go beyond their natural ranges, dynamic equilibrium may be lost, often resulting in adjustments in the ecosystem that might conflict with societal needs. In some
circumstances, a new dynamic equilibrium may eventually develop, but the
time frames in which this happens can be lengthy, and the changes necessary to achieve
this new balance significant.
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