Owner/Client
The Nature Conservancy
Location
Paint Rock, Alabama
CEC Services
- Survey
- Permitting Support
- Site Characterization
- Construction Oversight
Owner Objective
The Nature Conservancy and the U.S. Fish and Wildlife Service (USFWS) developed a partnership with a mutual goal of improving the aquatic habitat in the Paint Rock River, by removing a low water concrete crossing that functioned as an aquatic migration barrier during low flow conditions. Historic dredging and channelization left the river system inherently unstable and in a state of continual adjustment.
Channel dimensions within the study reach were altered due to the flow and sediment transport disruptions from the concrete crossing. Upstream of the crossing, the river was in a state of lateral adjustment and sediment aggradation. In conjunction with the crossing removal, the secondary goal was to stabilize and arrest massive bank erosion upstream of the crossing for approximately 750 linear feet. The project was funded under the USFWS Landowner Incentive Program (LIP) grant administered by The Nature Conservancy.
CEC Approach
CEC’s design, using a combination of bio-engineering and natural channel design techniques, aimed to reduce bank heights and angles by excavating a bankfull bench and providing a shallow bank angle upstream of the crossing.
Several single arm boulder vanes were installed along the outside of a meander bend of the Paint Rock River, where bank shear stress was high. Installation of the boulder vanes reduced near bank stress, enhanced aquatic habitat, optimized local sediment transport, provided bank stability, and dissipated excess energy into the downstream pool. CEC’s design and construction took into consideration federally protected aquatic fauna and their habitat. CEC worked with the USFWS stream team to construct the project .
