Hawaii officials for years have talked about the need to retreat from isle coastlines as sea level rise models show large swaths of the state’s shorelines inundated by waves and increased flooding.

But for Waikiki, a major economic driver for the state, tourism officials and the state Department of Land and Natural Resources are advocating another path: staying put through at least 2080.

To do so, complex new projects will have to be executed, likely at an extraordinary cost, and questions remain as to whether some of those will be feasible based on state laws that restrict hardening of shorelines.

DLNR’s top coastal lands official, representatives from local coastal engineering firm Sea Engineering, and Rick Egged, president of the Waikiki Beach Special Improvement District Association, briefed the board that oversees DLNR on the overall vision for Waikiki’s coastline earlier this month. The plans are embedded in an environmental impact statement spanning hundreds of pages that must get a sign-off from the Board of Land and Natural Resources, which sets policy for DLNR, before it can be forwarded to Gov. Josh Green to make a decision on whether to approve it.

The EIS is just the first step, after which projects will need to obtain numerous permits and approvals, not to mention funding.

The environmental review, as required by new state rules, examines multiple projects along the shoreline to help understand them in a holistic manner and how they might affect one another, Michael Cain, administrator for DLNR’s Office of Conservation and Coastal Lands, explained to the Land Board during its July 14 meeting.

The scope of the environmental analysis has already been winnowed down, however. The Waikiki shoreline stretches from Duke Kaha­namoku Beach to Kaimana Beach, a stretch of about two miles, or 10,260 feet of coastline. Cain, who took over as head of OCCL last year, said it was his understanding the EIS at one point considered the entire coastline, but it was decided the project area was too big.

The scope has been narrowed to an area roughly half that size that spans major resorts along four beach sectors referred to as Fort DeRussy, Halekulani, Royal Hawaiian and Kuhio.

“While the other beach sectors of Waikiki — Duke Kahanamoku, Queens, Kapi‘olani, and Kaimana — were not selected for beach improvement and maintenance actions, these areas are clearly important and, as sea levels continue to rise, additional actions may be necessary in these beach sectors in the future,” the EIS, which was completed by Sea Engineering, states.

Costs unknown

Plans include periodically moving hundreds of cubic yards of sand along the Fort DeRussy Beach sector to widen it and every 10 years mining large amounts of sand from offshore to replenish the Royal Hawaiian Beach sector. Each sand replenishment project fronting the Royal Hawaiian area is expected to take about four months.

Along Kuhio Beach, DLNR hopes to periodically pump sand from offshore and build a segmented breakwater to buffer waves.

Along the Halekulani beach sector, which spans approximately 1,450 feet of shoreline from the Fort DeRussy groin to the Royal Hawaiian groin, the state is proposing to build three new T-shaped groins, essentially rock walls that jut out into the ocean, and a new L-shaped groin adjacent to the existing Fort DeRussy groin, as well as improving upon the existing groin that extends out from the Royal Hawaiian.

The state then hopes to bring in 60,000 cubic yards of sand from offshore to create 3.8 acres of new dry beach. The series of groins is designed to create four arch-shaped beaches.

The cost of the projects along these four sectors is unknown. The EIS doesn’t provide an estimate. Cain told the Land Board that stakeholders reviewing an early draft of the EIS several years ago figured it would likely be hundreds of millions of dollars.

“So the decision was made just to pick one (project), show the concept can work and then expand outwards,” he said.

That project includes just one of the four beach cells envisioned for the Halekulani beach sector, a section spanning about 400 feet of shoreline. That project alone, which Sea Engineering is still designing, is estimated to cost about $20 million, according to the Waikiki Beach Special Improvement District Association, a coalition of Waikiki hotels and other businesses that have partnered with the state on the EIS and overall planning.

The project is being designed to withstand just 1.5 feet of sea level rise, meaning within 25 to 30 years following construction, it may be necessary to raise the elevation of the project by several feet, according to the EIS, so that it could last through 2080, when the ocean could rise by 3.5 feet.

It’s not clear how much more that would cost. The EIS also anticipates ongoing maintenance costs, including pumping in more sand as it gets pulled offshore.

It could take several years for the one beach cell along the Halekulani sector to get all the required approvals and permits, Cain told the Honolulu Star-Advertiser.

The project also needs to be fully funded. So far, the state has promised $9 million and the special improvement district association another $3 million, according to Egged.

He said he thinks obtaining full funding for the first beach cell from the state and private sector is feasible, but when it comes to the projects spanning the four beach sectors, federal funding will likely be needed.

“Overall, I think it is feasible to get the whole job done,” Egged said.

Seawall quandary

Funding is just one of many challenges facing the proposed projects, portions of which have already received push-back from community groups concerned about environmental impacts, harm to surf breaks and the costs to local taxpayers. The projects for the Halekulani beach sector also would require a new wall be built along the shoreline in front of the resorts, which state officials aren’t sure is allowed under state law.

More than two decades ago, the Land Board adopted a “no tolerance” policy that forbids new seawalls, which have caused miles of sandy beaches, including those along Waikiki, to erode. Additionally, in 2020 the Legislature passed Act 16 to shore up prohibitions against shoreline armoring. The law prohibits building seawalls, revetments and other shoreline hardening structures in areas with sandy beaches and at sites where the structures interfere with recreational and ocean activities.

Lawmakers passed the measure with the aim of safeguarding the state’s dwindling number of beaches. In the case of Waikiki, however, the natural beaches were long ago destroyed by seawalls, which accelerate erosion and prevent beaches from naturally migrating landward.

Some 37 seawalls were built in Waikiki in the early part of the 20th century, and by about 1920 walls lined most of Waikiki Beach, according to the EIS. The armoring quickly devastated the beaches. As a result, for decades massive volumes of sand from offshore and other locations has been brought in to replenish the beaches in Waikiki, and groins and other structures were constructed to try to retain it. The engineered beaches are now almost entirely composed of imported sand, according to the EIS.

“I actually have conflicted feelings when I look over the history,” Cain told the Land Board. “There are times when I am horrified, like look what we have done and we can’t go back. And then there are other times I look at it and think, we’ve maintained a world-class beach in an urban environment.

“It’s definitely a managed area that incorporates a lot of natural elements. But it is managed. I don’t know how we can go back to the dynamic shorelines that I prefer, the ones that are allowed to erode and accrete over the seasons.”

‘Sand retaining wall’

But as officials try to move forward on efforts to further shore up the Waikiki coastline amid the daunting impacts of rising seas and increased storms in the coming years, it’s not clear if those plans will be able to circumvent more stringent laws and policies aimed at protecting sensitive coastal areas and encouraging the removal of beachfront buildings and infrastructure.

Land Board Chair Dawn Chang questioned how the proposed wall along the Halekulani beach sector could be built given the prohibitions laid out in Act 16.

“How do we get past (Act 16), where we have been told by the Legislature that you can’t build seawalls?” Chang asked David Smith, a coastal engineer with Sea Engineering who briefed Land Board members during this month’s hearing. “This is an 8-foot-tall seawall.”

“These seawalls are specifically designed not for beach restoration; it is to protect the private properties,” she added.

Chang said she worried about the response DLNR would receive from beachfront property owners in other parts of the state who want a seawall but are denied.

But Smith said it wasn’t a seawall but rather a “sand retaining wall.”

“I don’t believe this one is there to protect private property,” he said. “It is a design element to protect the beach.”

“It doesn’t protect (the Halekulani hotel). It keeps the sand from spilling into their property.”

The EIS downplays the need for the wall, saying that within the Halekulani beach sector it may be necessary to increase the height of existing seawalls or build new walls to retain the sand and prevent wave overtopping. But Smith, under questioning by the Land Board, said the proposed wall is actually critical to the project.

Without the wall, he said, “it wouldn’t be considered an effective project, in my mind.”

Cain, whose division is the primary applicant on the EIS, told the Star-Advertiser in a subsequent interview that he didn’t know if the new wall would violate Act 16.