U.S. Army Corps of Engineers Completes Phase 2 of Flood Mitigation Measures in Mendenhall River Valley in Juneau, Alaska

JOINT BASE ELMENDORF-RICHARDSON - The U.S. Army Corps of Engineers announced Friday the second phase (Phase 2) of temporary flood mitigation measures in the Mendenhall River Valley in Juneau, Alaska, designed to increase protection for the capital city under threat by the glacial lake outburst floods (GLOF).

"The Corps of Engineers has a legacy of solving America's hardest problems, and right now this is one of America's hardest problems. Thanks to President Trump's unparalleled leadership, Senator Sullivan's ferocious advocacy, and the Army's commitment to Building Infrastructure, Not Paperwork, the protection we've delivered to the citizens of Juneau this year far exceeds last year's capability," said Adam Telle, Assistant Secretary of the Army for Civil Works. "The City and Borough of Juneau has also been an outstanding partner in this effort, and we look forward to continuing our innovative collaboration to get after this problem."

The Corps' announcement on Phase 2's completion follows Senator Dan Sullivan's leadership in advancing the Water Resources Development Act (WRDA) out of committee last week. This legislation is a key step toward accelerating USACE's long-term response to Juneau's flooding.

"We cannot have the capital of one of our most important states, Juneau, Alaska, endure this flooding every summer. It's unacceptable," said Alaska U.S. Senator Dan Sullivan. "Thank you, Assistant Secretary Telle, for your great leadership on this."

"The HESCO barriers are now complete as a short-term solution," added Senator Sullivan. "The WRDA bill we passed out of committee last week empowers the Army Corps to rapidly solve this crisis for Juneau while we continue working on medium- and long-term solutions."

Under Public Law 84-99 Advance Measures, USACE installed 2.72 miles of gabion baskets along the Mendenhall River, armored 1.85 miles of riverbank to prevent erosion, and constructed a 1,100-foot-long earthen berm to protect Back Loop Road and downstream areas. This builds on the highly effective Phase 1 barriers installed in spring 2025, which covered 2.5 miles between Marion Drive and Rivercourt Way, incorporating important lessons learned from the 2025 GLOF.

"I am proud of the work we have done to complete Phase 2 of our GLOF mitigation efforts," said BG Joseph Goetz, commanding general of USACE - Pacific Ocean Division. "I want to thank the City and Borough of Juneau for their strong partnership with the U.S. Army Corps of Engineers, and for their continuous efforts to mitigate the threat of the glacial lake outburst flood. 'Building Infrastructure, Not Paperwork' is all about pushing USACE to move quicker, with velocity, to make sure Americans, Alaskans and all the great people of Juneau are protected from flood danger."

In October 2025, USACE signed a Public Law 84-99 Advance Measures agreement with the City and Borough of Juneau (CBJ) to fund both Phase 2 barrier installation and Phase 1 repairs at 100 percent federal cost. To date, Phase 2 has cost approximately $35 million, involving over 30,000 contractor labor hours and 7,000 USACE project delivery team hours.

"Our community is heading into a 2026 glacial lake outburst flood with a much higher level of protection than we have ever had," said City and Borough of Juneau Deputy City Manager, Robert Barr. "The USACE's Advanced Measures program and its teams have helped to protect thousands of homes, businesses, properties - including schools and critical infrastructure - to a degree that we could not have accomplished on our own. We are incredibly grateful, not just for their work on Phase 2, but for their collaboration across all aspects of this ongoing disaster."

USACE provided 81,000 linear feet of temporary flood barriers, 500 super sacks, and 112,500 sandbags from its National Flood Fight Materiel Center in Illinois for 2026. Ahead of this year's GLOF, USACE also shipped 41 pumps to Juneau and cut roughly 200 downed trees that were already in the Mendenhall riverbed to reduce debris strikes on the gabion baskets.

To address overtopping risks near neighborhoods and the Mendenhall River Community School, USACE, CBJ, and the U.S. Forest Service opted to build an efficient low-maintenance earthen berm along the lake side of Back Loop Road. Located on two acres of Forest Service land between Back Loop Bridge and Chelsea Court, the berm stands 10-12 feet high and 50-60 feet wide.

Additionally, USACE and CBJ hosted emergency preparedness trainings in April and July alongside federal, state, tribal, and NGO partners. These public sessions covered flood response equipment, scenario planning, and barrier tours, culminating in a July community event focused on sandbagging, pump plans, and flood risk awareness.