Posted on April 7, 2025
ASAN, Guam — Naval Facilities Engineering Systems Command (NAVFAC) Marianas has kicked off emergency repairs on the Glass Breakwater in Apra Harbor ahead of schedule, marking the first significant step in a $571 million multi-year project to restore and strengthen the vital coastal structure.
“This project strengthens Apra Harbor and aligns with NAVFAC Marianas’ mission to deliver resilient infrastructure that supports Fleet capabilities and island logistics,” said Capt. Troy Brown, commanding officer of NAVFAC Marianas. “We are focused on stabilizing the structure, ensuring safe operations, and maintaining project momentum through disciplined oversight and coordination. This effort demonstrates NAVFACs’ role in planning, designing, and executing projects that enable mission readiness and enhanced warfighter lethality throughout the Indo-Pacific.”
Rear Adm. Brent DeVore, commander, Joint Region Marianas, observed the first armor stone lift. “The Glass Breakwater was built by the Navy Seabees following World War II in the 1940s, and has not only been a mainstay of Apra Harbor since that time, but is critically important to the military mission on Guam,” DeVore said. “Today’s milestone, therefore, represents the Department of Defense’s commitment to the island, and reflects the importance of this infrastructure to support our warfighters.”
Rear Adm. Greg Huffman, commander, Joint Task Force-Micronesia (JTF-M) was also invited to witness a critical step in the repair process. “Advancing the joint military mission in Guam and the region begins with significant investments in the island’s infrastructure,” Huffman said. “These upgrades to strengthen and harden the Glass Breakwater are vital to not only the
operational capacity of Apra Harbor ensuring military readiness but also support the Commercial Port of Guam to supply necessary goods to the entire island.”
The Glass Breakwater, which shields Apra Harbor and the Port of Guam from strong waves and storm surges, was severely damaged by Typhoon Mawar in 2023. Classified as “failed” by the U.S. Army Corps of Engineers, the breakwater had continued to deteriorate, prompting NAVFAC Marianas to accelerate assessment and repair timelines.
The project’s early start is credited to rapid coordination, innovative assessment methods, and early contractor engagement. The initial phase involves relocating large armor stones—each weighing 10 to 15 tons—from the breakwater’s crest to its most damaged sections. These stones are packed tightly to form a temporary barrier, reducing further damage and ensuring continued access to critical repair zones.
Joe Patterson, PE, NAVFAC Marianas waterfront project manager, said post-typhoon assessments provided critical insights into areas where wave action had displaced armor stones and exposed the breakwater’s inner core.
“Although we couldn’t safely access the most damaged sections on foot, the use of drone imagery and coordination with the U.S. Coast Guard gave us a clear picture of the conditions,” Patterson said. “That rapid assessment helped us move quickly to secure funding and begin targeted repairs, ensuring we stayed ahead of any further deterioration.”
The design team used specialized software to analyze drone imagery and measure each armor stone’s size and weight, allowing for the accurate selection of stones that could be relocated using equipment already available on island. The long-term design includes the use of large interlocking concrete armor units, each weighing approximately 42 tons. These will be transported by barge and trailer and placed from the center of the breakwater outward in both directions to enhance stability against wave action.
“The biggest challenge will be setting the toe of the structure underwater,” Patterson added. “It requires advanced technology, precision crane work, and a little cooperation from Mother Nature. Once in place, the breakwater will be strong enough to handle wave events with a 25-year return period.”
To ensure construction safety, the contractor has deployed two nearshore buoys that provide three-day wave forecasts. Typhoon readiness plans are also in place to protect personnel and equipment during storm conditions.
Design work began in October 2024, with in-water construction expected to start by August 2025 and completion scheduled for July 2029. The project was awarded to TPC-NAN, a joint venture based in Sylmar, California, under the Navy’s SIOP Multiple Award Construction Contract.
