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WESTERN IOWA STREAMS FISH PASSAGE IMPROVEMENT PROJECT, IOWA
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Completed in 2001
For more information contact:
U.S. Fish and Wildlife Service
Columbia Fishery Resources Office
608 East Cherry Street
Columbia, MO 65201
| Project Description: |
Approximately 800 bridge
crossings on Missouri River tributary streams in western Iowa are
threatened by streambed degradation. Local agencies are
partnering to stabilize these bridges by manipulating the natural
streambed grade in the area. Grade control structures are being
constructed with a 4:1 downstream slope, with a vertical elevation
of 2 to 25 feet above the pre-construction streambed. Unfortunately,
the unintended consequence of streambed grade stabilization has
been a precipitous decline in native fish populations because many
of these structures are believed to be functioning as barriers to
fish migration. |
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Streamed grade
control preventing fish passage |
Renovated
streambed providing fish passage |
| Project
Outcome: |
This project
modified six structures on Walnut Creek, a Missouri River tributary,
to a 20:1 downstream slope. Follow- up evaluation showed this action
restored fish passage capabilities at these structures. |
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| Benefits: |
All modifications
restored 60 miles of stream habitat for channel
catfish, flathead catfish, flathead chub, Topeka shiner, paddlefish
and sauger. |
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| Partners: |
The Hungry
Canyons Alliance, Iowa Department of Natural Resources, USDA Natural
Resources Conservation Service, and Iowa
State University. |
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