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.
For more information about ...
- ... pre-historic shoreline change, see Prehistoric beach accretion rates and long-term response to sediment depletion in the Columbia River Littoral System, USA,
- ... converting paper maps to digital shorelines, see Historical Map Recovery using Multiple, Integrated ESRI Programs, or
- ... calculating shoreline change rates using GIS, see Coastline Mapping and Identification of Erosion Hazard Areas in Pacific County, Washington.
