As a measure that would increase the shoreline setback for structures and development advances through the City Council, a building industry professional is raising questions about other mitigation efforts to account for sea level rise.

Currently, the shoreline setback is 40 feet for most properties, unless it is subdivided, which would increase it to 60 feet.

Bill 41 would increase the base shoreline setback to 60 feet and establish a formula that takes into account the beach erosion at each specific property. So the new minimum shoreline setback would be calculated by taking the minimum 60 feet and adding 70 times the erosion rate at each property. However, that amount would not be more than 130 feet.

Urban Honolulu from Pearl Harbor to Kahala would be subject to only a 60-foot setback and would not have to include the erosion rate.

The Honolulu City Council passed the measure unanimously through second reading Wednesday, although Council members Carol Fukunaga, Esther Kia‘aina, Calvin Say, Augie Tulba and Andria Tupola voted with reservations.

Architect Kristan Eiserloh, who owns Eiserloh Architects, which specializes in designing oceanfront residential projects, was concerned about Bill 41.

One idea he suggested instead of the setback is to have deeper foundations for homes that are at risk of flooding due to sea level rise.

“When the floods come in, they take out the soil that’s around the foundation, and then your foundation collapses and it breaks,” he said. “So the way you address that is you have to build the foundation deeper into the ground.

“You could require that as a department and say, ‘On oceanfront projects, your foundation has to go 4 feet lower than the existing grade.’”

He currently gives the owners of the properties he works on the option of building deeper foundations than what’s required to withstand changes to the sea level. However, because it is more costly, they often decide not to do so.

“The owners that I work with, a lot of them are in their 50s and 60s, and they’re like, ‘Well, I’m only going to be here another 25 years. So design the house for 25 years. I don’t care what happens to it after that.’ They don’t care what happens in 75 years,” he said.

“Some of them do. … The ones that pass it down to their kids, they’re going to say OK, but then the other thing they say is, ‘I’ll let my kids worry about it at that point in time.’ There’s only so much money that people want to throw into the ground. I mean, you could throw hundreds of thousands of dollars into the ground and it will never be a factor in your lifetime.”

Eiserloh added that because properties will be allowed to remain on their current setback as long as they do not do any more development to their homes other than repairs to the bathrooms and kitchen, people will either do other development illegally or the properties will fall into disrepair.

“The rich guys aren’t going to be impacted. The other guys are going to get impacted, the people that have had property in their families or people that bought them years ago for $600,000 or $800,000. They’re not rich, they just live there,” he said.

Eiserloh also said that some properties that are on high sea cliffs, such as parts of Portlock, should not be subject to the increased setbacks because their homes are already high enough away from the water.

However, University of Hawaii Director of the Climate Resilience Collaborative Chip Fletcher pushed back against that during Wednesday’s Council meeting.

“It was alleged that the (State of Hawaii Sea Level Rise Viewer) in the area of Portlock is an error. It is not an error. It shows wave run-up, wave splash related to a meter of sea level rise,” he said.

“The area of Portlock, which is a rocky shoreline, will experience intense wave run-up and wave splash under a meter of sea level rise, so that was not an accurate characterization.”

Fletcher added that sea level rise is permanent.

Office of Climate Change, Sustainability and Resiliency Executive Director Matt Gonser wrote in the office’s testimony that Oahu has already lost 5 miles of beach due to coastal erosion and that sea level rise would affect 3,800 existing structures if no action is taken.

Kia‘aina and Tupola voted with reservations on the measure because both wanted to make sure that the affected communities would have their voices heard and that the government should take the time to consider what their role is in helping people transition away from the coastline. Both were especially concerned about multigenerational families that have passed down their property, and both the financial and emotional costs that further setbacks would have on them.

Fletcher did point out that when Maui updated its shoreline setbacks to the same standard as Bill 41, the National Flood Insurance Program reduced flood insurance rates for the island, which could save homeowners some money.

Say was concerned about the public infrastructure located within urban Honolulu, which also would be heavily affected by sea level rise, as according to the state’s sea level rise viewer, many of those areas also would be underwater with a 3.2-foot rise in sea level.

“I’m scared too because most of our public infrastructures are in the coastal zone areas, our airport, reef runway, sewage treatment plan that’s on Sand Island, county power,” he said.

“For me this is just paper. We’re going to adopt it, nobody is going to execute. … You may have this formula in place of the 130-feet setback. But other than that, what’s next? … My priority is that we’d better start thinking about our city and county public infrastructures that are going to be affected.”

The measure will again be heard at a future Zoning and Planning Committee meeting.