Washington's Coast
Washington State Department of Ecology

WAVES
STORMS
 
EROSION
What's
happening

Ocean Shores
Cape Disappointment
Washaway Beach
Westport
Leadbetter Point
dams
jetties
Winter storm damage to Westhaven State Park beach near Grays Harbor South Jetty, 2001
Westport: South Jetty shoreline changes
Following construction of the Grays Harbor South Jetty in the early 1900s, South Beach grew seaward. As the jetty deteriorated, a spit developed at Pt. Chehalis. After the jetty was repaired, the spit and the beach near the jetty eroded, forming Halfmoon Bay. During the 1950s, South Beach began to erode. But repairs to the South Jetty did not halt erosion.

US Army Corps of Engineers add fill to the beach south of  South Jetty, Grays Harbor Severe storm damage
Severe winter storms topped the South Jetty during 2001. In 2002, the US Army Corps of Engineers filled the eroding beach near the jetty with 125,000 cubic yards of dredged material.
  • Waves erode the beach near the South Jetty
    In 1993, storm waves plowed through Westhaven State Park into Halfmoon Bay, threatening Westport's wastewater treatment plant, aquifer, and sewer outfall.
  • Ongoing erosion and repairs
    In 1994, the US Army Corps of Engineers filled the eroded area at Westhaven State Park with 600,000 cubic yards of dredged material. The erosion continued; waves washed away 10,000 cubic yards of sand per year from the site. In 2002, the US Army Corps of Engineers filled the eroding site again. Repairs to the beach totaled nearly $12 million.
What's happening near the South Jetty?
  • High wave energy
    Wave action is too intense for sand to build up. As waves bounce and refract around the Grays Harbor ebb-tidal delta, they focus energy. The steep slope of South Beach also allows bigger waves to break closer to shore.
  • Summer sand loss
    During the summer, sand is carried south along beaches by littoral drift. The Grays Harbor entrance, delta, and jetties may block this flow of summer sand, reducing the sand supply.
  • Winter sand loss
    During the winter, sand is carried north along beaches by littoral drift. The South Jetty may interrupt this flow of winter sand, decreasing the sand supply to Halfmoon Bay.
  • Small offshore bars
    Offshore bars help buffer beaches against pounding wave action. Near South Beach however, offshore bars are relatively small.
South beach erosion and dune scarps Erosion south of the South Jetty: During the winter of 2001, storm waves sliced into the foredune, creating a scarp along the beach.
Source: The Southwest Washington Coastal Erosion Study.
 
Images courtesy of: Brian Voigt, Greg Pelletier

Southwest Washington Coastal Erosion Study. A recent study of Washington's coastal processes and shoreline changes.

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