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.