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https://nap.nationalacademies.org/catalog/27432/critical-issues-in-transportation-for-2024-and-beyond

Where the River Meets the Road: How Washington State is Providing Habitat while Protecting Highways

The configuration of today‘s road system owes more to historic travel routes, and transportation needs than to regard for ecological and fluvial processes. Roads are often located along rivers where they are subject to periodic damage from seasonal high flows and severe storms. The traditional response is to protect the roadway with rock armoring to stabilize eroding banks and fend off the water‘s force. This work, as maintenance or emergency response, may need repeating if it only addresses a symptom. Threats to the roadway and risk of road closures may continue. This approach can also result in significant loss of aquatic habitat in the ongoing cycle of damage and repair. Severe weather, high flows and flooding exhibit increasing frequency and intensity Washington State and elsewhere. Projections for climate change show this trend continuing. How can the problems with repetitive maintenance while improving aquatic habitat be reduced? Washington State Department of Transportation (WSDOT), working closely with Washington Department of Fish & Wildlife (WDFW) established the Chronic Environmental Deficiency (CED) program, where projects are developed and implemented with the goal of optimizing habitat improvement. This allows specialized focus on long-term solutions beyond the scope of maintenance or emergency response. Sites with repetitive maintenance concerns are nominated by WSDOT, WDFW, Tribes or others and evaluated against program criteria. WSDOT conducts a reach assessment, reach analysis, or corridor analysis that identifies the hydrologic mechanisms for failure and develops a conceptual design solution. A scientifically based prioritization methodology provides ranking based on ecological gain and effectiveness of the correction. Since 2004, WSDOT has successfully completed seven CED projects with an investment in excess of $10 million. Engineered logjams have worked both as bank stabilization and as mid-channel flow diffusion structures on the Hoh, Nooksack and Clallam Rivers. Bridges that were replaced Nolan Creek have restored channel migration. Buried woody groins on the Snoqualmie and Newaukum rivers have protected shorelines as predicted. The Hoh River project, WSDOT‘s largest CED project to date, involves some of the world‘s largest engineered log jams. Monitoring for ongoing assessment of structural integrity, geomorphic changes, and biological performance is in development. There are currently 13 CED projects funded for $50 million to be constructed by 2010. About 30 additional projects are currently included in the CED process. During recent winters these projects held up very well to historic floods. Defining road projects based on environmental as well transportation needs is a path to more comprehensive, long term solutions. This approach demonstrates the importance of detailed reach analysis and effectiveness of bioengineering technique, and has wide application for transportation professionals adapting to change.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Features: Photos; References;
  • Pagination: pp 504-511
  • Monograph Title: Proceedings of the 2009 International Conference on Ecology and Transportation (ICOET 2009)

Subject/Index Terms

Filing Info

  • Accession Number: 01558570
  • Record Type: Publication
  • ISBN: 9780977809448
  • Files: TRIS
  • Created Date: Mar 31 2015 9:06AM