Armor stone replacement to reinforce Grays Harbor North Jetty

The U.S. Army Corps of Engineers (USACE) has awarded a major contract for the rehabilitation of the Grays Harbor North Jetty, a critical coastal structure designed to stabilize the harbor entrance and protect the federal navigation channel. The project targets storm-induced damage accumulated over decades, with works focusing on restoring structural integrity and hydraulic performance.

Extending nearly two miles into the Pacific Ocean, the North Jetty functions as part of a dual-jetty system that controls sediment transport and wave action at the harbor entrance. Repeated exposure to high-energy wave climates and overtopping during severe storm events has progressively displaced armor stone and reduced the crest elevation and width, compromising the jetty’s ability to dissipate wave energy effectively.

The awarded contract, valued at approximately $30 million, includes repairs along a 1.4-mile section of the jetty, concentrating on the most vulnerable zones where erosion and structural degradation are most pronounced. The primary engineering intervention involves the replacement of displaced armor units using large quarry stones, combined with reconstruction of the crest profile to restore the original design geometry.

Construction methodology will rely on land-based heavy equipment operating along the jetty alignment. This approach enables precise placement of armor stone and controlled rebuilding of the crest, ensuring that the structure regains sufficient mass and interlocking capability to resist future storm loading. The rehabilitation also aims to improve resistance to wave overtopping, a key factor in long-term deterioration of coastal protection structures.

The North Jetty plays a fundamental role in maintaining safe navigation conditions for deep-draft vessels accessing the Port of Grays Harbor. By confining tidal currents and limiting sediment intrusion into the navigation channel, the structure ensures operational reliability for one of Washington State’s primary bulk export gateways. Any reduction in its effectiveness could lead to channel shoaling, increased dredging requirements, and disruption of maritime operations.

Originally constructed beginning in 1898, the jetty has undergone multiple rehabilitation cycles throughout the 20th century. Historical interventions, particularly in the mid-1900s and 1970s, involved large-scale placement of armor stone to counteract settlement and storm damage. The current project continues this long-term maintenance strategy, reflecting the ongoing need to adapt coastal infrastructure to persistent environmental loading.

The rehabilitation highlights the importance of maintaining crest elevation and armor stability in rubble mound structures. Loss of crest height reduces freeboard, increasing overtopping rates and accelerating internal erosion processes. Similarly, displacement of armor stone weakens the structure’s ability to absorb and dissipate waves, leading to progressive failure if left unaddressed.

The project is expected to extend over multiple construction seasons, with completion targeted toward the end of the decade. Once completed, the restored jetty will enhance resilience against Pacific storm systems and ensure continued protection of the navigation channel and surrounding infrastructure.