River restoration freeboard design requirements
River restoration projects are complex structures involving a multitude of hydraulic approaches to develop a river ecosystem that is intended improve habitat for targeted species (animal and plant). These designs are often put together with extensive modeling and design efforts. It has been noticed during water up and operation of constructed river restoration projects that water surfaces through the system are often higher than the designs and models predict. The research question this proposal addresses is how different are the water surface elevations between design and actual? It is assumed that these water surface elevations are typically higher than designs and numerical models predict for the low flows and the difference decreases at higher floodplain flows. Little post construction data has been collected and analyzed making selecting an acceptable freeboard for channel and stream design difficult.
Need and Benefit
Reclamation has the responsibility to meet the requirements of the Endangered Species Act and court mandated Biological Opinions in protecting and preserving 13 species of salmon and steelhead. The PN Region in coordination with Columbia Salmon Recovery Office have been designing and aiding in the construction of many river restoration projects. Most projects are put out for specification and are not evaluated after construction. Monitoring constructed projects would help designers with future projects and help identify necessary main channel freeboard requirements.
Columbia Salmon Recover Office currently has many projects in the pipeline for design and construction. These projects are both being designed by Reclamation employees and IDIQ contractors. Understanding better how to design river restoration projects will aid in faster and more robust river restoration designs from both parties. Existing restoration projects that Reclamation is working on include Bird Track Springs, Barkley Bear, Bursteadt Lane and the Murderers Creek Ranch, all these projects could benefit from this research project.
This project will work perfectly into recently completed restoration projects that have been activated. Waiting to complete this work may result in a missed opportunity for some of the data collection. River restoration projects are often designed to naturally evolve over seasons. Comparison between design and actual needs to be performed before the natural evolution of a system take place.
Contact the Principal Investigator for information about partners.
Bureau of Reclamation Review
The following documents were reviewed by experts in fields relating to this project's study and findings. The results were determined to be achieved using valid means.
River Restoration Freeboard Design Requirements (final, PDF, 1.5MB)
By Bryan Heiner
Report completed on September 30, 2020