( vegetated mechanically stabilized earth without a hard toe) exhibited vulnerabilities to damage and soil loss under the same flow conditions.
In addition to performing the laboratory tests, the research project also included visiting sites throughout the country to observe the long-term performance of various biotechnical measures in the field. Teams were sent out to gather design and performance information and compare those results to what was found in the laboratory. From the field visits, the team developed a comprehensive compendium database that will be published with the final report, providing information on practical methods gained from field experience in a searchable database format.
At NCHRP Reynaud applauds the study for giving verifiable backup to the use of vegetation such as willows as a natural streambank protection technique.
“ With the willow, this is actually something that’ s growing and substantial. Now we can demonstrate that this is a better way to go,” he said.“ We’ re using something that’ s naturally occurring but in a way that’ s verified and tested in an engineering manner.”
Beyond the research advancing the state of engineering practice, Reynaud praises the project team, led by Lagasse and Clopper, for its top-notch work.
“ Pete puts together the best project teams that we’ ve ever worked with. They are the cream of the crop,” he said.“ Ayres always delivers on time, and Pete is legendary.”
Ultimately, Shields says the research project provided a
For a time lapse video showing the willows growing at the Colorado State University greenhouse, please visit https:// www. youtube. com / watch? v = JAV7GSQvgcc
thorough study that addressed real-world problems.
“ It added a nice chunk of engineering to the base of experience that practitioners can use. This gives engineers more confidence and an ability to control risk in a cost-effective fashion,” he says.
Ultimately, Lagasse says that the biggest benefit of the research is to provide a guidance resource for engineers.
“ It gives tricks of the trade, lessons learned, and quantitative information on how to measure whether vegetative components are performing as designed,” he said.“ It provides step-by-step guidelines on how to design biotechnical protection methods.”
Lagasse said while this research only tested two methods in the laboratory, he sees a potential for testing many more methods, such as vegetative riprap, an approach favored by many transportation agencies, in a similar way, as funding is available.
“ For the first time we have an approach to do this,” he said.“ The Ayres / CSU team proved it could be done, and we developed a protocol to do it.”
Project sets out to protect streambanks
The City of Fort Collins, Colorado, has been busy practicing some of the stream restoration techniques that were tested as part of the National Cooperative Highway Research Program’ s( NCHRP) environmentally sensitive streambank protection research project – namely using a combination of vegetation and rock toe to protect streambanks.
The City’ s Stream Restoration and Habitat Enhancement project involves stabilizing stream channels, restoring and creating new native in-stream and riparian habitat to attract and support fish and wildlife, and promoting best management practices to improve water quality in streams throughout Fort Collins.
Sue Paquette, project manager for Fort Collins Utilities, says this project benefits the community by making the floodplain more stable, mitigating erosion, stabilizing channel banks, and enhancing water quality.
“ This helps make the area more ecologically diverse and hopefully brings back native species and fauna to the riparian corridor,” she said.
Fort Collins Utilities is working with Ayres Associates as part of a multidisciplinary group of experts on the streambank protection project. Dusty Robinson, civil engineer in Ayres Associates’ Fort Collins office, is heading up the project for Ayres, which is part of a five-year contract with the City. In all, about 40 sections of streams in Fort Collins will be evaluated, with