The U.S. Army Corps of Engineers (USACE) Honolulu District has completed an Engineering Documentation Report that provides a new recommended plan for the Ala Wai Flood Control Project. The new report provides a technical evaluation of the flood control system with modifications designed during the past year.

In its press release, USACE stated, “the new plan incorporates significantly less impacts on the natural streams and residential properties within the watershed, and focuses on evacuating the water without detaining it in the upper reaches of the watershed valleys. Using this report as the foundation, the project team will now begin the evaluation of costs, economic benefits, and environmental impacts through a supplemental National Environmental Policy Act (NEPA) and Hawai‘i Environmental Policy Act process (HEPA) process.”

The Ala Wai Canal was listed on the Hawai‘i Register of Historic Places in 1992. The canal was built between 1921 – 1928, initially as a channel with natural banks. Constructed lava rock walls were added in 1934-35 to protect the banks by using federal funds available through employment and public works programs during the Great Depression.  In the 1950s, the walls were reinforced with concrete. Features associated with both development periods contribute to the historic significance and would be affected by the flood control project.

Historic Hawai‘i Foundation commented on the previous plans, expressing concerns about the effect of the project on historic resources both in the mauka areas and at the canal. HHF is also a concurring party to the Army Corps of Engineers Programmatic Agreement that establishes a design review and mitigation process to resolve effects on historic properties from the project. HHF will be reviewing the new study and providing additional input and comment as needed.

The report and a map showing the current proposed project design changes and new feature recommendations are available on the USACE’s Ala Wai project webpage: https://go.usa.gov/xfARb.

Opportunities for community input will be posted to that webpage over the next several weeks. A public scoping meeting as part of the NEPA/HEPA process is planned for later this year. Questions about the project or the report can be emailed to: AlaWaiFloodProject@usace.army.mil.

Image from the U.S. Army Corps of Engineers’ Engineering Documentation Report.