Coastal Change

Barrier Evolution: The Columbia River littoral cell is made up of four low-lying barrier beach plains that have developed over the past several thousand years.  Field research by Study investigators has uncovered evidence to document the evolution of the littoral cell's barrier beaches.  Research components include: mapping and dating linear dune ridges, ground penetrating radar (GPR), soil profiles, auger coring, vibra-coring, quantifying pre-historic accretion rates, and dating dune scarps from episodic earthquakes events.

Shoreline Behaviour: In contrast to the moderate net beach accretion over the past several thousand years, changes to the littoral cell have occurred much more rapidly since the late 1800s.  Landscape modifications, such as the construction of dams and jetties, as well as changes in the way humans use natural resources (dredging at the mouth of the Columbia River, irrigation projects in the upper river basin), have combined to significantly alter the rates and extents of change along the littoral cell coast.  To analyze shoreline change since the late 1800s, shorelines mapped on National Ocean Service topographic sheets (NOS t-sheets) and derived from aerial photography have been converted into digital format (GIS coverages).  Quantifying historical shoreline change is one step in predicting future shoreline conditions.

Beach Monitoring: The beach morphology monitoring program was initiated in 1997 to document short-term (storm event), seasonal to inter-annual (El Niño) changes in beach form.  A description of the techniques used to measure changes in the beach and initial results of the monitoring program (1997 - 2000) are presented, including beach profiles, topographic mapping with the CLAMMER, sediment sampling, and surveying nearshore bathymetry with the coastal profiling system.

Bathymetric Change: Regional bathymetric data is being analyzed to understand the historical changes in nearshore morphology, the availability of sediment to nourish the littoral cell coast, and whether these changes correlate with an evolving shoreline position.  Regional data sets from 1926 and 1998 and annual data sets at the estuary entrances (Grays Harbor, Willapa Bay, and Columbia River) have been merged with data collected by the Study, including multi-beam (1999) and nearshore bathymetry (1998 - 2002).

Ecology - SEA Program | USGS - Coastal & Marine Geology

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Maintained by CMAP, Washington Department of Ecology
Address questions and comments to George Kaminsky
Modified 22 Mar 2012