Special Sessions
Sponsored by the Geomorphology Specialty Group
Association of American Geographers 103rd Annual Meeting
San Francisco, California, April 17-21.

Blackwell Lecture on Geomorphology and Society

Paper Session 3304
Thursday, 4/19/07, from 11:50 AM - 12:50 PM

Sponsorship(s):

Geomorphology Specialty Group

Organizer(s):

Anne Chin - National Science Foundation

Chair(s):

Anne Chin - National Science Foundation

Abstract(s):

• 11:50 AM Author(s):
  *George Mathias Kondolf - University of California
  

  Abstract Title: River Restoration in North America: Meandering Channels for All?

  
  

  River restoration has become a big business in North America, with over 40,000 projects (costing over $17 billion) in the US since 1990. Many of these projects involve new, essentially experimental treatments, but there has been remarkably little monitoring and objective post-project appraisal, limiting the advance of the science and practice of river restoration. Among the most imageable river restoration projects are those that involve creation of a new channel, often in a new alignment and generally with dimensions and form different from the pre-project channel. These channel reconstruction projects often have the objective of creating a stable, single-thread, meandering channel. This is commonly the case even on rivers that were not historically meandering and whose sediment load and flow regime are not consistent with such channel forms, and despite research showing that dynamically migrating channels (not stable channels) have the greatest ecological richness. These meandering channels are often specified by the Rosgen classification system, a popular restoration design approach. While most such projects have not been objectively evaluated, available data indicate a high failure rate. Nonetheless, this classification and form-based approach continues to be popular because of its ease of application, its accessibility to those without formal training in fluvial geomorphology, and probably because it satisfies a deep-seated (though unrecognized) cultural preference for single-thread meandering channels, consistent with 18th century English landscape theories that held the serpentine form to be ideal, and satisfying public preferences for tidy landscapes and the idealized trout stream.

  Keywords: river restoration, fluvial geomorphology

  
  

Session Description: This invited annual lecture series features G. Mathias Kondolf of the University of California, who will speak on the science, practice, and challenges of river restoration in North America. The Blackwell Lecture on Geomorphology and Society is sponsored by Blackwell Publishing, Inc. and the Geomorphology Specialty Group of the Association of American Geographers.