Vegetated Riprap Survey of Highways in South Central and Interior Alaska

This report documents and presents the results of a site study of riprap armored stream banks along Alaskan highways. The study's intent was to evaluate and determine the governing parameters of a successful hybrid environment using rock to stabilize the stream banks in concert with vegetation to maintain healthy riparian habitat. In order to design and build riprap revetments that successfully incorporate, support and promote successful revegetation on a sustainable basis, design and construction engineers require quantitative limits on the governing parameters. This evaluation was performed to support the development of engineering design guidelines for successful vegetated riprap installation. Study sites of focus were located along Alaskan highway/stream interfaces where riprap was designed and installed to protect stream banks and bridge structures. For each study site, a combination of factors needs to be present in order to enable and encourage a successful hybrid environment of bank protective riprap coexisting with thriving vegetative reinforcement. The factors investigated during site evaluation include hydrologic and hydraulic, regional, existing riprap characteristics, and plant species present. Findings of this study indicate that site specific hydrologic and hydraulic characteristics need to exist for a riprap armored stream bank to allow and sustain vegetative growth. In addition, given a vegetative friendly riprap structure, this study found that Alaska's diverse regional climate influences species composition.


  • English

Media Info

  • Media Type: Web
  • Edition: Final Report
  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 71p

Subject/Index Terms

Filing Info

  • Accession Number: 01103976
  • Record Type: Publication
  • Report/Paper Numbers: FHWA-AK-RD-05-08
  • Contract Numbers: T2-05-05
  • Created Date: Jul 1 2008 2:44PM