Juneau — The U.S. Army Corps of Engineers has taken a central role in planning an enduring flood‑control approach for the Mendenhall Valley, telling the City and Borough of Juneau Assembly that it will prepare a technical report and planning‑level cost estimate with a target completion of May 2026.

John Rajik, a civil engineer with the Alaska District of the Army Corps, said the study team will work with contractor AECOM to develop and evaluate five conceptual alternatives: a flood‑control dam, levees/floodwalls, bypass channels, a Suicide Basin lake‑tap tunnel to transfer water to Mendenhall Lake, and infrastructure relocation. Rajik said the planning effort will include a preliminary design for the preferred alternative, a planning‑level cost estimate and a draft environmental assessment.

Public Law 84‑99 advanced measures and phase 2

Daryl Downing, the Corps’ Seattle District public law 84‑99 program manager for phase 2, described the program’s eligibility requirements and confirmed the governor’s written request for Corps assistance was accepted. Downing told the assembly that the Corps will provide advanced measures assistance at 100% federal cost for procurement, engineering and installation of temporary flood protections under the Corps’ authority, but operations, maintenance and rights‑of‑entry remain a local responsibility after installation.

View Drive: temporary barriers not recommended

Corps technical staff emphasized that Hesco‑style temporary barriers are not a safe, whole‑community solution for View Drive. Mike Records, the Corps’ hydraulic engineer on the project, said site conditions — porous moraine soils, seepage potential and constrained access — make a neighborhood‑scale Hesco alignment prone to seepage and costly bank stabilization and that a breach could “create a lake that would inundate all of View Drive.” The Corps noted several homeowners have had individual success with temporary measures, but said the PL 84‑99 program cannot fund measures for individual private lots; it supports community‑scale solutions.

Timing and next steps

Rajik said the next months will focus on establishing evaluation criteria, narrowing conceptual alternatives and producing a planning schedule tied to a May 2026 target. The Corps plans a December planning meeting to agree on evaluation criteria and then to move forward with an agreed alternative; Rajik said the team expects the preferred alternative could be a combination of measures but that, given schedule constraints, the technical report will focus resources on a single preferred plan (which could combine approaches).

Community consequences and operations

Downing and other Corps staff said the Corps will procure materials and may install barriers for the phase‑2 alignment, but once installed the City and Borough of Juneau will be responsible for permitting, rights‑of‑entry, operations, ongoing maintenance and eventual removal. Corps staff also said pumps, technical assistance and training could be provided to support local operations around temporary measures.

Evidence: Corps briefings to the Committee of the Whole and the signed addendum to the cooperative agreement during the meeting recess.