Satellite images of hurricanes Kilo, Ignacio and Jimena taken over the weekend were remarkable and historic, in a notably unsettling way: They marked the first time that three major hurricanes have been recorded over the Pacific Ocean simultaneously since storm records have been kept.

All three were classified as Category 4 storms on Sunday, carrying with them massive rain and winds as they churned across the Pacific. Though Hawaii has so far avoided the worst of their effects, anyone who experienced the 10- to 15-foot waves that Ignacio sent to the eastern coasts of our islands on Tuesday can attest to the power of these systems and the threat they represent.

The U.S. Army Corps of Engineers understands the special vulnerability of the most densely populated part of Hawaii if what is described as a “100-year-flood” overwhelms the Ala Wai Canal and submerges low-lying Waikiki. That’s why the Corps is proposing a mitigation plan that would protect an estimated 3,000 properties against likely destruction and safeguard the area’s 54,000 residents.

NOAA

The main components of the 1,835-page draft environmental impact analysis and feasibility study, which is open for written comment through Oct. 7, are fairly straightforward: New repositories for potential flood waters from the three streams that feed into the Ala Wai, strategically placed earthen berms to contain rising water, concrete barrier walls up to 4 feet high surrounding the entire canal and three new pump stations.

Under development for the past 14 years, the current draft doesn’t include some of the more dramatic mitigation measures that were considered and rejected along the way, including extending the Ala Wai through Kapiolani Park and creating canal barrier walls as high as 14 feet.

Still, the plan’s price tag is an estimated $173 million, which would be funded in large part by the federal government, with about one-third of the cost expected to be covered by the State of Hawaii.

The plan is expected to be refined over the next year before being taken up by the Corps for final approval in January 2017. The proposal would then be forwarded to Congress.

Any protections envisioned by the Corps might be needed before then. According to Derek Chow, the lead official for civil and public works at the Corps’ Honolulu office and the principal author of the plan, the kind of devastating flood the plan anticipates “will absolutely happen. It’s just a matter of when.”

The effects of climate change may hasten the matter of when. Rising temperatures around the globe are increasingly catalysts for more frequent, larger and destructive storms. The El Nino weather system that gave rise to Kilo, Ignacio and Jimena is turning out to be the strongest in 65 years, and isn’t expected to peak until sometime between October and next January.

As though the growing potential of major storms and threats to life and property weren’t enough to take into account, those reviewing the plan must also consider that Waikiki is the key driver in Hawaii’s leading economic sector, tourism. About 79,000 visitors are in the area on any given day, and their spending funnels billions of dollars into our economy, supporting businesses and jobs.

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Interruption of that economic activity would have ripple effects throughout Hawaii, but an unmitigated, lasting disruption would have a disastrous impact on tens of thousands of individuals’ ability to meet our state’s astronomical cost of living and likely result in no small number of businesses closing for good.

A major flood requiring a recovery period of that length or longer in Waikiki would have far more significant consequences. Given that such an event would likely be accompanied by major effects on other parts of Hawaii, state disaster resources would be spread even more thinly, making recovery more difficult.

Leaders in Waikiki are engaging with the plan. Waikiki Neighborhood Board chair Robert Finley was optimistic about the plan’s most visible and possibly controversial component, the four-foot wall around the canal. A well-designed wall might have aesthetic appeal and prevent people from falling in the Ala Wai, Finley said.

We were less impressed with state Rep. Tom Brower’s cavalier response. While we agree with his observation that sound evacuation plans are important in preparing for floods, we also think investing in the Corps’ plan makes more sense than resigning ourselves to storms as unavoidable risks from which you “probably just have to take your lumps and rebuild,” as Brower said.

To his credit, U.S. Sen. Brian Schatz told the Civil Beat Editorial Board on Tuesday that the Corps’ plan “holds great promise.”

“If we can get a community supported plan that the Corps feels it can execute, I’d certainly make it a priority” in the federal funding process, said Schatz, who is a member of the Senate Appropriations Committee.