Kaua’i, first county to regulate devt on sea level rise forecast

Kaua ‘i, the fourth largest island of Hawaii, became one of the first counties to enact proactive development regulations based on scientific modeling projections of sea level rise.

“Today is truly a historic day as I sign this bill into law,” Mayor Derek Kawakami said in a statement.

The new building ordinance, which became effective October 14, amends construction design standards to incorporate expected sea level rise impacts.

The Kauaʻi County Council unanimously approved the Bill, No. 2879, on October 5, 2022.

The county’s Planning Department worked with the University of Hawai‘i at Mānoa’s Climate Resilience Collaborative on the progressive measure.

“Kaua‘i is no stranger to the impacts of climate change, as we’ve seen in the floods of 2018 and the recent historic south swell and king tides in July which resulted in significant infrastructure damage,” Mayor Kawakami said. “This new ordinance ensures that the inevitable effects of coastal erosion and flooding are determining factors in the future growth and development of our island.”

A bill-signing ceremony was held October 14 at the Līhu‘e Civic Centre’s Mo‘ikeha Rotunda, with more than 25 representatives from various agencies and organisations involved in the creation and passing of the bill attending the event.

“I want to thank the Planning Department and its leadership for this first-of-its-kind landmark policy that will also help other municipalities as a model to better prepare for our future,” said Council Vice Chair Mason Chock, who also serves as chairperson for the Council’s Planning Committee. “Government is often known to be reactive, so it’s nice to see a proactive approach from Kaua‘i County.”

The signed ordinance creates an updated Sea Level Rise Constraint District in the Comprehensive Zoning Ordinance to address sea level rise impacts on annual high wave run up and passive flooding that’s projected to occur within this century.

The ordinance requires the lowest floor of all new residential construction, and substantial residential construction improvements, to be elevated two feet above the highest sea level rise flood elevation. It also requires all new non-residential construction, and substantial non-residential improvements, to be elevated at least one foot above the highest sea level rise flood elevation.

“Living on a small island in the middle of the Pacific Ocean, there’s no ignoring the threat of climate change on our natural and built environments,” said Ka‘āina Hull, the county planning director. “This bill is a result of years of hard work and collaboration and sets a new standard for planning policies which previously have been based solely on historical data and events. We’re incredibly grateful to all involved in this groundbreaking effort that will propel Kaua‘i toward a more secure and resilient future.”

In collaboration with the Planning Department, the UH Mānoa Climate Resilience Collaborative (formerly the Coastal Geology Group) helped draft Bill No. 2879 to incorporate its innovative computer model projections. The modeling shows areas across the Hawaiian Islands where chronic coastal flooding and erosion are expected to occur as sea level rises in the coming decades.

These projections are reflected in an online atlas called the County of Kaua‘i Sea Level Rise Constraint District Viewer. Elevation design standards outlined in the new ordinance are based on annual high wave run up and passive flooding hazards obtained from the viewer.

“The Climate Resilience Collaborative has worked closely with the Kauaʻi County Planning Department to fine-tune the data to ensure the highest quality and create a stand-alone viewer that can be used as a planning tool,” said Chip Fletcher, interim Dean of the UH Mānoa School of Ocean and Earth Science and Technology and director of the Collaborative.

Fletcher said the United Nations’ latest Intergovernmental Panel on Climate Change reports say with high confidence that sea level rise will persist for “centuries to millennia” due to ongoing warming of the oceans and melting of the ice sheets.

“There is nothing we can do to stop sea level rise,” Fletcher said “This measure will minimize the threat to public health and safety, promote resilient planning and design and minimise the expenditure of public money for costly flood control projects necessitated by accelerating sea level rise. Kaua‘i is providing an example for coastal communities around the nation of the next right step in building community resiliency to climate change impacts.”

Other partners involved in the drafting of Bill No. 2879 include Hawai ‘i Sea Grant, Department of Land and Natural Resources, the Pacific Islands Ocean Observing System, SSFM International and Sea Engineering.