Bureau of Reclamation Banner

Improving Public Safety of Large Wood Installations

Project ID: 689
Principal Investigator: Connie Svoboda
Research Topic: Sediment Management and River Restoration
Funded Fiscal Years: 2013
Keywords: large wood, large woody debris, public safety, boater safety, river restoration

Research Question

Large wood installations are an important component of Reclamation's overall river restoration strategy due to the many realized benefits of large wood structures. Liability associated with large wood installations has become a widely discussed topic within the river restoration community. Wood structures can pose a public safety hazard to river recreational users such as boaters, swimmers, fisherman, and children. Installing large wood structures in rivers can produce what are known in the boating community as "strainers". Flow through or flow underneath the structure can pin boaters or swimmers against the structure or pull them under the water surface. Large wood structures also produce an attractive location for fishing, playing, and climbing. Design features such as structure porosity, structure orientation, log submergence, percent river obstruction, and use of cables and metal bars affect the safety of the structure. Public safety is typically considered during the design process; however, there appears to be lack of cohesive information on this topic. The goal of this scoping-level study is to identify specific research gaps on safety issues and determine the best way to address these gaps in order to design and install safer large wood structures. It is anticipated that a physical model, numerical model, or guidance document may be the focus of future research.

Need and Benefit

A technical workshop on Large Wood Applications and Research Needs in River Restoration was hosted jointly by Reclamation & U.S. Army Corps of Engineers in February 2012 (funded by S&T program). The primary goal of the workshop was to provide an opportunity for individuals and agencies actively working in the field of the engineered placement of large wood to collectively develop a road map for future large wood research needs and priorities. The opening discussion at the large wood workshop included a discussion of recent legal developments in the State of Washington related to large wood installations. David Eckberg from Skellenger Bender, P.S. discussed relevant case law, current legislative efforts, and the roles of designers, clients, public agencies, and environmental managers relating to placement of wood in rivers.

The road map and summary report from the workshop (in draft) identify the need for design criteria to improve the safety of structures as high priority. Results from the workshop show that this is a topic of interest to many people in the field of river restoration within Reclamation, Corps of Engineers, other federal agencies, local agencies, and private firms. Once future direction for this work has been determined, specific partners will be identified and listed in future proposals.

Landowner concerns about public safety and liability have stalled Reclamation-led large wood projects on the Methow River (personal communication, Terril Stevenson, Reclamation PNRO) and on Nason Creek (personal communication, Mike Sixta, Reclamation, TSC), both in Washington. Research conducted in the area of safety of large wood structures can be used to augment Reclamation's large wood manual and serve as a singe point of reference for design and installation of safer wood structures.

Contributing Partners

None

Research Products

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.

Improving Public Safety of Large Wood Installations: Scoping Proposal Report of Findings (final, PDF, 91KB)
By Christopher Cuhaciyan, Sean Kimbrel and Connie Svoboda
Report completed on September 30, 2013

Large wood structures are an important component of Reclamation's overall river restoration strategy. However, large wood can pose a public safety hazard to river recreational users. This scoping-level report identifies research gaps on safety issues and determines how to address these gaps in order to design and install safer large wood structures. Researchers explore four major topics relating to safety issues of large wood structures: public safety, structural stability, liability, and risk.
Keywords: large wood, large woody debris, engineered logjams, public safety, stability, risk, liability

This information was last updated on September 17, 2014
Contact the Research and Development Office with questions or comments about this page