Each boulder is the size of an SUV and weighs between 18,000 and 32,000 pounds.
The boulders cover the Rialto Spit near La Push, Washington, and repel the force of the ocean waves so that the nearby village stays safe and dry. That’s why the boulders are called armor rock.
The Rialto Spit is a sandbar that extends out from Rialto Beach. On one side of the spit is the Pacific Ocean; on the other, the mouth of the Quillayute River. A protective layer of rock, called a revetment, deflects water and debris. The revetment keeps the sandy ground of the spit intact and protects the village. But over time, storms have carried many of the rocks away. The result is that the spit isn’t as well protected as it once was.
The U.S. Army Corps of Engineers plans to repair the revetment over the next 10 years. This winter, about 200 feet of the revetment will be repaired with new armor rock and other materials.
Protecting the Quileute Tribe
La Push is located on the land of the Quileute Tribe. Just beyond the Rialto Spit lies a marina, a U.S. Coast Guard station, and many homes and businesses.
The Quileute have fought hard to preserve their community and their ancestral connection to the ocean. In the future, the tribe plans to relocate many buildings uphill from the coast so that they will be protected from tsunamis or storms. In the meantime, the revetment repair is essential in protecting La Push and members of the tribe who live there.
The Long Haul
Armor rock is hauled 200 miles by truck from Washington Rock Quarries in Orting. Because of the size and weight of each boulder, one truck can haul two to four pieces of armor rock at most. There are other quarries closer to La Push, but only Washington Rock has the type of materials that meet the strict specifications for armor rock.
Materials for the repairs must meet guidelines set by the U.S. Army Corps of Engineers. Armor rock must resist the erosive effects of waves and be the right density. The material also needs to remain structurally sound in freezing temperatures. The test to measure freeze-thaw stability takes up to four months to conduct. Before the project began, Washington Rock’s armor rock had already met all of the Army Corps’s guidelines.
Producing the Big Stuff
A typical blast at Washington Rock’s Kapowsin Quarry doesn’t produce many rocks that are big enough to be called armor rock. So Trade West Construction, the contractor repairing Rialto Spit Revetment, uses a special blasting method to produce more rocks of the right size. The revetment repairs this winter will use around 1,000 of these rocks.
Andy Leavitt, director of Trade West, has traveled all over the world for his company, building and repairing breakwaters, jetties, and revetments like the one in La Push. He has fine tuned the process of finding the right sources of rock and getting all of the equipment to the job site.
The most difficult project Leavitt has done involved taking apart heavy construction equipment and shipping it to an island off the coast of the Philippines where it had to be put back together.
Trade West plans to finish the revetment repairs in La Push by the end of February.
To learn more about La Push and the Quileute Tribe, visit the Quileute Tribe’s website.
Learn more about Washington Rock’s contributions to the Rialto Spit Revetment Repair project on our Projects Page.