JOINT BASE ELMENDORF-RICHARDSON --
Project Manager Reflects on Austere Conditions at Cape Lisburne, Mission Success for Seawall Construction
By Maj. Kathryn Hermon
USACE Alaska District
Far away, on the northwest tip of Alaska, sits a remote, strategic military site nestled between a small mountain range and the unforgiving Chukchi Sea. Against this desolate backdrop, a few hours after midnight on Aug. 12, 2020, the U.S. Army Corps of Engineers – Alaska District oversaw the placement of the final rock in a mile-long seawall to cap off a monumental arctic engineering and construction effort at the Cape Lisburne Long Range Radar Site.
With the precise positioning of this last rock, the project delivery team rejoiced on a job well done. Here at the edge of the Last Frontier, the completed barrier will protect critical military infrastructure from storm damage for the next half century.
“What an exciting project, and just a cool part of Alaska,” said Colleen Jordan, project engineer at the Alaska District. “I didn’t expect this type of civil works project to be so complex and so interesting. I’ve done work in other remote parts of the state, but the Cape Lisburne project was just so uniquely Alaskan.”
Beyond the challenges of blasting, crushing and placing rock on a narrow strip of beach between a steep mountain and the ocean, the team successfully navigated past logistical and environmental hurdles to keep the project moving forward. These obstacles included contending with icecaps, battling with monstrous waves, coordinating fuel barge landings and relying on charter flights despite unpredictable weather conditions. In addition, encounters with polar bears, grizzlies and walruses slowed or delayed work at the job site.
Located approximately 570 miles northwest of Fairbanks and about 40 miles northeast of Point Hope, the radar site operated by the Pacific Air Forces Regional Support Center provides aerospace surveillance to detect and allow for an early response to potential threats to North America.
At Cape Lisburne, the impacts of climate change were apparent. With erosion and significant storms in 2011 and 2012, the existing rock seawall began to fail in its protection of the runway. As the primary avenue for moving personnel and supplies, reconstruction of this important structure quickly became a priority.
The Alaska District began construction of the new seawall in the summer of 2016 and with tireless focus, the endeavor took five full work seasons to complete. Because of the cold and harsh climate of Alaskan winters the construction season is limited to just six months a year.
The project work included quarrying the needed rock and placing it in accordance with the seawall design that was developed by the district’s Hydraulics and Hydrology Section.
“The seawall was designed for a 50-year return period wave condition,” said Merlin Peterson, the Alaska District’s designer of record for the project. These measures will ensure that the structure withstands wave action from the fiercest storms.
Despite the project’s remoteness, a rock quarry was conveniently located nearby on property managed by the U. S. Fish and Wildlife Service. Four different rock sizes were required for the seawall, ranging from the largest armor rock that weighed 15,000 pounds to the smallest filter rocks that measured two-to-six inches in size.
Once the rock was excavated and prepared, it was carefully placed on the seawall with a long-stick hydraulic excavator. Most of this activity occurred underwater. Excavator operators used a tiny computer screen and GPS to ensure correct placement. Much like a puzzle, the large armor rock had to be placed in a way that fit together and by design, layered in a way that dissipates the destructive force of waves.
For the last four years of construction, the contracted personnel worked in two 12-hour shifts. During the day, one crew blasted the quarry rock. At night, a second team placed rocks on the seawall. This schedule meant the crew did not have to stop for inbound aircraft that arrived during the day.
Furthermore, a dedicated maintenance team continuously worked on repairs. The rock that was mined on site was extremely abrasive and caused unprecedented wear to the equipment. Welders worked around the clock repairing teeth and edges on the excavator buckets.
Weather and waves not only affected the placement of rocks, but also logistics.
The transportation of personnel, food and supplies were at the mercy of harsh and turbulent weather. Fog and winds often hindered planes from landing. Bigger and heavier items, such as equipment and fuel, were commonly supplied by barge. However, this too depended on ocean conditions. Many of the barges remained offshore for days, waiting for the seas to calm before beaching.
Site operations continuously adapted to new challenges, even those with flippers.
Each year, construction crews adjusted operations to account for the presence of walrus in nearshore environments, primarily in the fall period. The district integrated marine mammal observers into the contract, who coordinated with on-site staff to implement temporary work stoppages when walrus either swam by or hauled out on nearby beaches located in the adjacent Alaska Maritime National Wildlife Refuge.
“The 611th Civil Engineer Squadron chose USACE to manage the project due to their unique expertise involving remote Alaska projects, and the unparalleled experience of the Hydraulics and Hydrology Section,” said Julie Mages, deputy base civil engineer for the 611th Civil Engineer Squadron at Joint Base Elmendorf-Richardson. “USACE and the Air Force worked hand-in-hand over five years to adapt and overcome many obstacles thrown our way throughout this challenging project.”
Mages’ words mirror the Alaska District’s mission to provide “a full range of quality engineering, science, technical and construction support services in support of peacetime and contingency operations in Alaska as well as across the Pacific Region and around the world.”
The successful accomplishment of this project strengthens the Alaska District’s reputation as the nation’s experts in arctic engineering and construction. Through perseverance and professionalism, the team can take pride in delivering an engineering solution that is built to last.
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