Wood deposits add roughness to channels, changing the sediment transport capacity, so that log jams often cause upstream aggradation resulting in changes in the elevation of the river bed. This can force a river laterally, where it may erode through forest buffers and into valuable riverside properties. Effective management of riparian zones addresses the ecological costs of river channelization as well as the economic costs of lateral migration, removing land and structures in their path.

10,000 Years Institute is on the cutting edge of research to examine the role of wood deposits in channel change. In 2002, we conducted field research to quantify change in bed elevation upstream of log jams and to characterize the response of low gradient channels to large jams, publishing the results with partners in the journal Geomorphology. We also worked with the Washington Department of Ecology to develop a guidance document for local jurisdictions to identify and delineate the boundaries of an active river channel, improving sustainability of development adjacent to rivers.

Please contact the Institute for a copy of the publication on change in bed elevation: Influence of vertical channel change associated with wood accumulations on delineating channel migration zones, Washington, USA.

See the Department of Ecology report for Channel Migration Zone Delineation at https://fortress.wa.gov/ecy/publications/documents/0306027.pdf.

Swipe between different years of imagery and LIDAR for WA state below. See if you can identify channel migration zones.