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ARS Home » Southeast Area » Oxford, Mississippi » National Sedimentation Laboratory » Watershed Physical Processes Research » Research » Publications at this Location » Publication #112727
Title: RESTORATION OF DEGRADED STREAM CORRIDORS USING VEGETATION: AN EXPERIMENTAL STUDY

Author
item PIRIM, TANER - UNIVERSITY OF MISSISSIPPI
item Bennett, Sean
item BARKDOLL, BRIAN - UNIVERSITY OF MISSISSIPPI

Submitted to: Laboratory Publication
Publication Type: Government Publication
Publication Acceptance Date: 6/1/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: To alleviate flooding in naturally meandering rivers and streams, both local and federal agencies artificially straightened many waterways. However, this channelization increased flow velocity and caused bed incision and channel widening, and decreased ecological habitat and habitat resources. The aesthetics of the channel also were disturbed. One method of restoring river meanders to a degraded stream is to introduce vegetation in alternating locations to divert the flow pattern and cause sediment deposition in select areas. Various aspects of stream restoration have been studied but the effect of vegetation density on meander potential is not well understood. In this study, a laboratory experiment was performed using alternating zones of simulated vegetation. The density of the vegetation zones was varied while all other flow characteristics were kept constant. A video technique was used to determine surface flow characteristics. Measurements revealed that as vegetation density increased, the tendency for the stream to meander also increased. This study established a methodology to induce sinuosity in straight, eroded channels using simulated vegetation. Such knowledge is important for action agencies involved in the rehabilitation of degraded streams and rivers.

Technical Abstract: To alleviate flooding in naturally meandering rivers and streams, local and federal agencies artificially straightened these waterways. However, this channelization increased flow velocity and caused bed incision, channel widening due to increased bank failure, and decreased ecological habitat. One method of restoring river meanders is the introduction of vegetation in alternating locations to divert the flow and cause sediment deposition. In this study, a laboratory experiment was performed in a flume with simulated vegetation zones. The density of the vegetation zones was altered while all other flow characteristics were kept constant. Particle Image Velocimetry (PIV) was used to determine surface flow characteristics. PIV measurements revealed that as vegetation density increases, the following flow parameters related to river meandering increase: average thalweg velocity, flow circulation downstream of the vegetation zone, sinuosity, reattachment length, depth, and resistance. The average flow velocity decreased both inside and outside of the vegetation zone. This study established a methodology to induce sinuosity in straight, degraded channels using vegetation and determined that placing roughness elements that simulate natural vegetation can significantly alter the flow direction.