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United States Department of Agriculture

Agricultural Research Service

Title: Invertebrate Response to Physical Habtat Changes Resulting from Rehabilitation Efforts in An Incised Unstable Stream

Authors
item Cooper, Charles
item Testa, Sam
item Shields Jr, Fletcher

Submitted to: Management of Landscapes Disturbed by Channel Incision Stabilization Rehabi
Publication Type: Proceedings
Publication Acceptance Date: March 30, 1997
Publication Date: N/A

Interpretive Summary: Sediments from our land and stream channels constitute the number one pollutant in America's waters. In several sections of the United States where streams are actively down-cutting through the landscape, stream habitat has been virtually destroyed. When state or federal agencies attempt to stabilize these actively eroding stream channels, they are provided with the challenge of restoring habitat as well. Many times physical habitat vital to fish can be restored at little extra cost. The question then becomes "How well and how rapidly do the streams natural plants and animals respond to the physical improvements?" This research discussed how the small animals that serve as fish food changed when habitat was improved in a field-scale study. This information is of interest to biologists who must use bio-indicator tools to measure stream conditions and the results of positive and negative changes in our environment.

Technical Abstract: Channel incision is a widespread phenomenon which results in a degraded aquatic environment. Past stream stabilization techniques have been shown to produce beneficial effects on the aquatic habitat, but design criteria for restoration of habitats in unstable sand bed warmwater streams have only recently been explored. To evaluate habitat rehabilitation criteria, a one-kilometer reach in an incised stream (Goodwin Creek) was modified to create greater water depth with riffle-pool sequences using in-stream structures (small weirs and spur dikes of quarry stone). Physical and biological changes that occurred at Goodwin Creek were compared to a similar incised creek which did not receive modifications (Bobo Bayou) and to a non-incised stream used as a reference (Toby Tubby Creek). Physical changes due to rehabilitation at Goodwin Creek included a 148% increase in mean water depth and a 67% decrease in mean velocity. Pool habitat increased from 20% to 66% of stream area. Following rehab, the riffle-pool sequence created in Goodwin Creek produced a different community of organisms which was subjected to a different set of environmental and biotic pressures, but generally indicated a more balanced community. 

Last Modified: 9/20/2014
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