The Army Corps of Engineers and the city have unveiled the latest proposal to protect Waikiki and neighboring communities against a potential flooding disaster.
The price tag, however, was placed at over $1 billion — triple the estimated cost of the project just five years ago.
The “tentatively selected plan” is detailed in the Army Corps’ 3,741-page Ala Wai Flood Risk Management Draft General Re-evaluation Report and Integrated Supplemental Environmental Impact Statement.
The document was published on the project’s website and presented at a news conference Friday morning at City Hall. It also appeared in the state’s latest online Environmental Notice.
The plan looks a lot like the “prospective plan” the Army Corps unveiled in April and billed as an early version of the tentatively selected plan.
The proposal still contains controversial berms and concrete walls around Ala Wai Canal.
According to the plan, flood walls averaging 6 feet high would be built around the length of the Ala Wai Canal, although it also calls for an elevated walking path on the walls — a feature the Army Corps contends will help soften unsightly impacts.
In the plan, the Ala Wai Golf Course would serve as a floodwater detention basin with an earthen berm built around the course 6 feet to 9 feet tall.
Both the golf course and flood wall projects would help minimize flooding risk for Waikiki and nearby communities.
Flood walls averaging 6 feet high would be built along Woodlawn Drive and Koali Road to reduce flooding risk to the Manoa area, while flood walls averaging 6 feet in height would go in along Kaimuki High School to reduce risk to communities east and southeast of the Manoa-Palolo Canal.
The $1.075 billion cost of the project caught some by surprise Friday, as the effort was originally priced at over $345 million in federal funds.
The project nearly doubled to $651 million in 2021 after the Army Corps proposed adding a four-story pump station to the Ala Wai Canal. That project was ultimately rejected in large part due to the added cost.
Among those who balked at the price tag then was Honolulu Mayor Rick Blangiardi, who asked the Army Corps to devise a new plan that would come within the federal appropriation.
The agency and the city agreed to focus the effort on handling more frequent 20- to 50-year storms rather than the rarer but more catastrophic 100-year storm.
Blangiardi couldn’t be reached for comment Friday, but he did have a quote in a news release issued earlier in the day. He described the new study as “a fresh look at solutions to ensure the safety of the hundreds of thousands of people that live, work, and play in Waikiki and the surrounding communities.
“This is about reducing the potential impacts of catastrophic flooding to our island and protecting transportation, access to medical facilities, and maintaining operations of our critical infrastructure for years to come,” the mayor said.
Under the latest proposal, the federal government would be responsible for 65% of the total cost, while the local government would pay 35%, or about $376 million.
In addition, the city would assume responsibility for operation, maintenance, repair and for any replacement and rehabilitation needs, at an estimated average annual cost of $359,000.
Sidney Lynch, president of Protect Our Ala Wai Watersheds, said she and other members of her group were surprised to learn how much the cost of the project has gone up.
“I haven’t had a chance to read through the whole document yet but I will be looking to see how they explain not including forest and ecosystem management in the plan, as this is the root of the flooding problem,” she said.
As for the 6-foot walls around the Ala Wai, Lynch said it’s likely a lot of people are still going to be complaining, even with the walkway built in.
“It’s still 6 feet at car level,” she said.
Earlier in the planning process, project engineers considered but rejected several proposed flood mitigation measures. They included creating a second outlet for the Ala Wai Canal and making Kapiolani Park a sizable detention basin.
Also removed from the plan were detention basins at Manoa District Park and Makiki District Park, along with the proposed Kanaha flood wall.
Officials additionally rejected proposed green solutions such as removing invasive trees and planting native ones in the watershed, saying that while they would have an effect on runoff and filtration, their impact primarily fell on storm events that happen every one or two years.
By December, project planners had narrowed the effort down to three potential action plans. One was focused on water storage, with detention basins to hold stormwater. Another was aimed primarily at water conveyance, featuring a variety of channels and flood walls.
The third was a hybrid plan featuring a combination of both, and that is the one that forms the basis of the plan outlined in the latest draft document.
The publication of the draft environmental assessment launches a 45-day comment period. Additionally, two public meetings will be held to accept verbal and written comments about document.
The first meeting will be from 5:30 to 8:30 p.m. Dec. 12 at the Mission Memorial Auditorium, 650 S. King St., in Honolulu. The second meeting will be virtual only from 5:30 to 8:30 p.m. Dec. 13.
For additional information, addresses and links, go to the project’s website at honolulu.gov/alawai.
Correction: An earlier version of the story had the incorrect amount the city would have to pay under the plan. The correct amount is $376 million.
