Regional Setting

The Columbia River littoral cell extends from Tillamook Head, Oregon to Point Grenville, Washington and has four major concave-shaped, offset sections of prograded shoreline separated by the Columbia River and two large coastal plain estuaries of Willapa Bay and Grays Harbor.  The sediment budget for the region is governed by the Columbia River, the second largest river in the United States and the largest river that discharges to the northeastern Pacific Ocean, with modern mean annual water discharge of 6,800 m3 s-1.  Wide and gently sloped beaches throughout the littoral cell front barrier-beach plains that have developed over the past several thousand years with large linear dune ridges and broad dune fields and swales.  The prograding barrier beaches along this tectonically active coastal margin have experienced episodic erosion and sudden 1 to 2 m subsidence events associated with large earthquakes of approximately 500 yr recurrence intervals.

The Columbia River littoral cell from Tillamook Head, Oregon to Point Grenville, Washington. Click on the image to link to a printable version.
 

Ecology - SEA Program | USGS - Coastal & Marine Geology

This is http://www.ecy.wa.gov/programs/sea/swces/overview/setting.htm
Maintained by CMAP, Washington Department of Ecology
Address questions and comments to George Kaminsky
Modified 14 Oct 2002