WESTPORT, Wash. - The Army Corps of Engineers is looking for public comment on a proposed long term plan for Westport's South Jetty.
Alternative 1b was detailed to Port Commissioners last December, and would rebuild the South Jetty 500 feet to the East of it's current location.
That point where the jetty ends is tied to the shoreline position on Half Moon Bay, so if we extend it to the East we have a wider dune with lower risk of breaching in the future. - Coastal Engineer David Michalsen
Michalsen said studies showed surfing at Half Moon Bay would not be impacted by the proposed change in surf.
The plan would also place 110,000 cubic yards of sand on the dune area between Half Moon Bay and South Beach, additional sand placement is expected to be triggered approximately every ten years or half as often as the current practice.
A public meeting will be held in Aberdeen, May 3, at the Port of Grays Harbor offices. The meeting will have an open house from 4:30 – 5:30 p.m. and formal presentation and public and agency discussion from 5:30 – 7 p.m.
GH LTMS Ltr Report EA March2012
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.