WA - In search for stronger shoreline, Ocean Shores can look to coastal neighbors
A 100-year old jetty used to protect Ocean Shores. Can new technologies save its south end?
Editor’s note: This is part two of two in a series about erosion on Ocean Shores’ southern shoreline. Part one outlined the threat of erosion to public and private infrastructure and emergency action from city officials; part two describes the driving factors of erosion, the framework for environmental resilience on the Washington coast, and potential long-term mitigation measures for Ocean Shores.
In 1916, the U.S. Army Corps of Engineers completed the construction of Grays Harbor’s North Jetty, a three mile-long berm of boulders jutting into the Pacific, hugging and holding the entire southern shoreline of Ocean Shores. The body of water now known as Oyhut Bay did not exist.
Today, a large remnant of that jetty, roughly 10,000 feet angling to the northeast from the peninsula’s western hoof to the Damon Point parking lot, lies stranded and submerged in the bay, battered by 100 years of bashing saltwater, waves and, once, the impact of an errant fishing boat.
During that time the shoreline has steadily abandoned the old jetty, retreating thousands of feet to the north. Erosion now threatens to cause millions of dollars of damage to public and private infrastructure.
While no environmental factor alone can fully explain the widening gap between the relic rocks and receding beaches, the shoreline owes much of its shape to the jetties protruding into the Pacific at Grays Harbor’s entrance.
“The erosion that you see in Oyhut Bay, and basically the development and expansion of the bay, is part of a very long-term process of the inlet entrance evolving in response to the construction of jetties,” said George Kaminsky, a coastal erosion expert with the Washington state Department of Ecology.
The biggest effect of the jetties, Kaminsky said, is “less sharing of sand going from north to south.” That phenomenon is evidenced by the altered alignment of beaches in Ocean Shores and Westport — the two peninsulas once paralleled each other, but as the North Jetty slowed southward currents and accumulated sand on the beach directly above it, Ocean Shores bulged to the west. From above, the mouth of Grays Harbor appears as a coastal jaw with an overbite.
That was by design — to keep sand out of the middle of the harbor and maintain a deeper channel for entering ships.
“The consequence is that you have deep water next to the shoreline and when the shoreline is no longer protected by the jetty, the shoreline is going to erode because deeper water allows bigger waves; bigger waves strike the shoreline and make the shoreline retreat,” Kaminsky said. “Are we dealing with a natural process? Are we dealing with a partly man made process? Or a combination of both?”
Kaminsky, who has studied coastal erosion in Southwest Washington for three decades, said those questions — the scope of the issue — will be crucial as Ocean Shores examines both emergency and long term solutions for resilience on its southern shoreline.
Currently city officials are scrambling to find an emergency buffer to protect property from forecasted king tides and storm swells this winter. With that measure in place, they’ll look to the future: Those extreme weather events could give a snapshot of rising sea levels due to climate change. In 2019 the University of Washington’s Climate Impacts Group produced a sea level rise predictor with beach-level specificity. For most of Oyhut Bay, the model gives a 50% chance water levels will rise by six inches by 2050, and anywhere from one and one-and-a-half feet by 2100, depending on emissions levels.