When it comes to building or rebuilding homes near Hawaii’s shorelines, property owners and the government officials charged with enforcing codes and protecting the islands’ fragile natural environment face increasingly difficult choices, exacerbated by global warming.
And so, when a developer came forward with a plan to build three new North Shore homes on “stilts” — near the Velzyland surf break and just a mile down the road from where a house fell into the ocean after high surf and coastline erosion undermined its foundation — it sparked a range of reactions among community members, preservationists and governmental bodies.
The City Council rightly approved the plan, which commits the developer to incorporate defensive measures against sea level rise and an encroaching shoreline. The planned homes are moved farther back from the shore than is currently typical, and they will be raised above the current sea level on those “stilts.” Instead of using a typical concrete foundation, the structures will stand on “micropiles,” which are high-strength bars 6 to 16 inches in diameter sunk 12 to 20 feet below ground level to be attached to the deep — and solid — coral substrate of an ancient reef that lies underneath.
Honolulu County permitting documents attest that the units will rise above flooding and high waves, even with 3.2 feet of sea level rise — predicted to occur by the end of the century — and withstand erosion of the sand and earth above its reef anchors. They will also be farther inland than other North Shore properties that are being undermined along Sunset Beach and Rocky Point.
Though its resolution opposing construction was overruled, the North Shore Neighborhood Board was also justified in expressing trepidation over new home construction in the North Shore’s coastal danger zone, where beach erosion and high waves are recurrent threats.
“The board has serious concerns about continued building along the coastline,” chair Kathleen Pahinui wrote. “Will the community have to pick up the costs later?”
To sort that out, it’s time for a coordinated plan for “managed retreat” that recognizes the effects of our overheated atmosphere. This should involve both county and state regulators, and encode standards for requiring retreat from the shoreline, with consideration of the regulators’ responsibility — if any — to aid affected property owners.
Dolan Eversole, a coastal geologist with the University of Hawaii Sea Grant College Program, belongs to the North Shore Coastal Resilience Working Group, which is urging the state and county to plan for managed retreat. Eversole called the plan to build on stilts “very smart,” but said the county and state governments should be looking for opportunities to acquire oceanfront land as public space, requiring landowners to move even farther back from the shoreline.
Planning that transformation in the way Hawaii manages its coastlines is bound to be a lengthy and complex process. All the more reason to begin now.
Many coastal landowners also need to make some hard choices, without delay. Recognizing that “temporary” sand burritos, boulders and seawalls change wave patterns and accelerate shoreline erosion, toughened rules and enforcement will make these destructive strategies far less likely. Property owners will need to find a workable, legal fix — or accept the need to retreat.
If the Velzyland plan works as intended, the design could foreshadow how resilient North Shore beachfront houses will survive in years to come. Just maybe, these new homes could still be standing when rising sea levels wipe out homes nearby.
