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
Destroyed home due to rapid erosion, Cape Shoalwater
Destroyed home due to rapid erosion, Cape Shoalwater The most rapid erosion
on the US Pacific coast

Washaway Beach, Cape Shoalwater, has been eroding an average of 100 feet per year for a century.

Cape Shoalwater: an eroding spit
 
During the early 1900s, Cape Shoalwater, a massive spit, began eroding rapidly. Between 1890 and 1965, the cape eroded 12,303 feet (3750 meters) at about 124 feet per year (37 meters).
Erosion at Washaway Beach, Cape Shoalwater
  • Past destruction
    During the 1920s, over 30 homes were claimed by erosion or relocated. In the years that followed, erosion destroyed a lighthouse, a life-saving station, a clam cannery, a school, and a Grange Hall. Erosion also forced the relocation of a cemetary and State Highway 105. In recent decades, erosion has destroyed 20 homes, private property, and part of the Willapa National Wildlife Refuge.
  • Transportation concerns
    In 1995, erosion threatened to undermine State Highway 105. There were also concerns that sea water could invade and damage cranberry bogs worth millions of dollars. To protect State Highway 105, the Washington State Department of Transportation constructed a $27 million submerged groin and beach fill area.
Why is this area eroding?

  • A moving tidal channel
    A tidal channel is deepening and migrating northward (an 8 to 12 year cycle.) As the channel migrates, it cuts into the shore.
A circular cycle
 
As the channel migrates northward, an underwater sand bar forms near the entrance of Willapa Bay. Waves push sand south, into Willapa Bay, forcing the northern channel to bend south. In time, the tidal channel breaks through the sand bar. The cycle begins again, as the separated sand bar moves to the center of Willapa Bay's entrance.
A circular cycle of channel migration
Cliffs at Cape Shoalwater created by rapid erosion Rapid erosion created cliffs along the beach in the Cape Shoalwater area. April, 1992. Dune ridges on Cape Shoalwater were once 49 feet high (15 meters).
Source: The Southwest Washington Coastal Erosion Study.
 
Images courtesy of: Brian Voigt

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

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