LIHU'E, Kaua'i — Consultants are halfway through a three-year study of Kaua'i's coastal erosion, which county officials hope to use to develop building setback regulations that take moving shorelines into account.

"It's important that we have scientific data on shoreline trends and future erosion hazards to help us develop appropriate management policies regarding construction and other types of development along Kaua'i's shoreline," Mayor Bryan Baptiste said.

But the study won't be done until 2008, and after that, the county will need to develop regulations to apply to local planning. Some properties might already be developed by then, and the County Council has proposed interim legislation — now under review by the Kaua'i Planning Commission — to revise coastal setbacks until the new data are available.

The county's present regulations, in place since 1971, establish a 40-foot building setback, but some properties have already been threatened by coastal erosion, which some owners have responded to by building rock or concrete walls.

Councilwoman JoAnn Yukimura said she would like to see setbacks in interim legislation moved dramatically landward on properties deep enough to support such setbacks — such as a 100-foot setback on properties with an average depth of 180 feet or more. She said new subdivisions along the coast should also take potential erosion into account when designing lots — creating lots in erosion-prone areas that are deep enough to allow owners to build well in from the eroding beach.

Yukimura said she expects the council to receive the Planning Commission's recommendations soon and to take up the legislation early in 2007.

Meanwhile, the county's coastal-erosion study, being performed by University of Hawai'i coastal geologist Charles "Chip" Fletcher, is collecting data and having the island's coastline photographed from the air. Some of its preliminary work is visible online at www.soest.hawaii.edu/coasts/.

Mayor Baptiste said he anticipates a county setback policy similar to that in place on Maui, in which setbacks vary according to the calculated erosion rate for the shoreline fronting specific properties.

ON THE WEB

www.soest.hawaii.edu/coasts

Reach Jan TenBruggencate at jant@honoluluadvertiser.com.