Officials are proposing to update Kauai’s existing policies on shoreline construction limits to reflect the latest scientific data on coastal erosion.

Bill 2461 calls for an update and tightening of the county’s shoreline setback law.

A group from the Kauai County Council, planning department, landowners, developers and community members have been meeting regularly over the past year to discuss and analyze ways to amend the existing law to better protect coastline properties, public access and shoreline resources. Officials seek to incorporate scientific data from a 2010 study on coastal erosion conducted by the University of Hawaii Coastal Geology Group.

The Kauai County Council’s Planning Committee expects to discuss the bill on Tuesday. At a recent meeting, the committee deferred the measure to review proposed amendments introduced by Committee Vice Chairwoman Councilwoman JoAnn Yukimura.

The 2010 study, "National Assessment of Shoreline Change: Historical Shoreline Change in the Hawaiian Islands," includes data on shoreline changes from 1927 to the present for Hawaii’s three most densely populated islands: Oahu, Maui and Kauai. According to Chip Fletcher, who leads the UH geology group, 70 percent of the beaches on the three islands are eroding.

The study concludes that beaches on Oahu, Maui and Kauai are eroding at an annual average rate of 4.8 inches a year.

Experts concluded Maui had the highest average erosion rate at more than 6 inches per year due to the island’s high rate of sea level rise, Fletcher said.

Kauai experienced a rate of just under 6 inches per year; Oahu saw the least erosion with a rate of 2.4 inches a year.

The setback, or distance from the shoreline in which no construction is allowed, on Kauai currently is based on the average depth of a lot. For shallow lots that are 100 feet or less, the minimum setback is 40 feet. For lots that are 121 feet to 140 feet deep, the minimum setback is 60 feet.

The current law was established in 2008 and amended a year later.

During the recent meeting, Yukimura presented a draft of proposed amendments, including a setback line of 40 feet plus 70 times the annual coastal erosion rate from the certified shoreline for lots averaging less than 140 feet. A mandatory 20 additional feet as a safety buffer is also being proposed to protect properties from episodic coastal events, sea level rise and other hazards.

The study concludes that continued monitoring of shoreline changes in Hawaii "is vital in the coming decades as the dynamics of the coastal environment that lead to beach erosion (for example, sea level rise, storms and waves) are likely to change with changing climate."

The U.S. Geological Survey plans to revise and update shoreline change rates every five to 10 years.

In recent months, high surf has particularly affected properties on Oahu. Large swells have wreaked havoc on several homes on the North Shore, where there has been significant shoreline erosion. Rocky Point residents were forced to use sandbags, tarps and other measures to protect their homes.

"Nature is giving a graphic example on Oahu that homeowners were experiencing due to the high episodic waves that are hitting our coastline," Yukimura said.

Sam Lemmo, administrator of the Office of Conservation and Coastal Lands, said climate change and sea level rise are significant consequences for an island state.

"We have 750 miles of coastline," Lemmo said. "We live on volcanic islands and most of our development is located in the flat coastal plain at relatively low elevation."

"It’s critical that we work on existing law," he added. "We need to plan for what’s going to happen in the future."

Shoreline-related issues and climate change are being discussed at the city and state level. The Honolulu City Council’s Zoning Committee recently heard a bill that would allow a shoreline property owner to apply for a minor-shoreline structure permit from the city Department of Planning and Permitting to construct retaining walls.

However, experts have said construction of seawalls, or shoreline hardening, should be avoided because the structures contribute to erosion of the beaches.

Yukimura said shoreline hardening is something Kauai County is trying to avoid by proposing that homes be built farther inland so they are not at risk of being swept into the ocean.

"We’re trying to design with nature or plan with nature," she added. "For the life of the house, they won’t be threatened by erosion based on the data we have now."

In the state Legislature, lawmakers are calling for a task force to address the affects of climate change. House Bill 1714 would establish one under the Department of Land and Natural Resources to develop a sea level rise vulnerability and adaptation report for Hawaii through 2050.

Under the measure, the Office of Planning will also establish and implement strategic climate adaptation plans and policy recommendations.

To access the "National Assessment of Shoreline Change: Historical Shoreline Change in the Hawaiian Islands" study, go to pubs.usgs.gov/of/2011/1051.