Clatsop Plains Shoreline Change

Clatsop Plains Shoreline Change Findings

  • Prior to jetty construction the beach was accreting at a relatively slow, uniform rate.
  • Immediately following jetty construction, the shoreline accreted rapidly along the northern part of the sub-cell and remained relatively stable along the southern part of the sub-cell.
  • The shoreline at the red transect (closest to the jetty) accreted most rapidly between the 1870s and 1920s.  The progradation exceeded 1000 m (3280 ft) during that time period.
  • By the 1920s, the beach at the northern end of the sub-cell began to stabilize or erode, while at the southern end of the sub-cell, the beaches began a period of rapid accretion.
  • By the end of the 1950s, accretion throughout the sub-cell began to taper off.
  • The length and height of the jetty combined with the sediment supply determines shoreline change.

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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