35th Street Corvallis, Oregon 97333 Dykaar, B.B., and Parker J. Wigington, Jr. 2000. Using a series of aerial photographs taken between 1936 and 1996, we trace coevolution of floodplain and riparian forest on the Willamette River. Size and internal structure of riparian forest patches reflect evolution of underlying barforms or channel beds.
Avulsion appears to cut new channels only short distances.
Given the central role of bars and islands in building new floodplain habitat, we identify their area as a geomorphic indicator of river-floodplain integrity. Dams, riprap, logging, and gravel mining may all be contributing to diminished bar formation rates. Removing obstacles to natural riparian forest creation mechanisms is necessary to regenerate the river-floodplain system and realize its productive potential.