Spreckelsville group seeks sand dredging

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SPRECKELSVILLE - Six beachfront owners on Stable Road are asking the Board of Land and Natural Resources for permission to renourish the beach, and for the first time on Maui they propose to use sand dredged from offshore.

The project would also include four "Geotubes," like big sleeves filled with sand and extended into the water like groins. The tubes would help slow the loss of sand from the beach but are removable and are considered to have a much less significant impact on the beach than seawalls.

The board will consider the application today in Honolulu, and later the proposal will have to come to the Maui County planning director for a minor special management area permit or the Maui Planning Commission for a major SMA.

A project like this has not really been studied on Maui, or even in Hawaii, according to Zoe Norcross-Nuu, the Maui Sea Grant Coastal Program extension agent. So the proposal includes a three-year follow-up study.

"It's like a privately-funded scientific experiment," said Planning Consultant Robb Cole on Wednesday.

Three other beach renourishment projects have been tried to the east of Stable Road, at Laulea and Sugar Coves. The results of the latest strategies have been good, according to Patty Cadiz and Barbara Guild, who offered their advice to the Stable Road owners. The Sugar Cove renourishment project won a national award in 2000.

Successful beach nourishment is a two-step process, says Cadiz. First, stop the beach recession. Then, put mobile material in front of it and let the ocean move it "where it needs to be."

The Stable Road project will take advantage of a master Conservation District Use Application that the BLNR established in 2000. This simplifies the permitting process for beach projects using less than 10,000 cubic yards of sand.

If the board approves the application today, it will be contingent on renewal of the State Programmatic General Permit, which is up for renewal of its blanket Water Quality Certificate from the Department of Health.

One difficulty faced by beach nourishment projects has been the DOH's antipathy to "fines," smaller-than-sand particles that come with sand mined from some inland locations.

Guild considers this objection overwrought. The water is cloudy, she agrees, but only for a short time.

Anyway, some dredged sand comes up without fines, so that problem could be eliminated. Dredging is much more expensive, Cole said.

The supply of land sand is running low. But National Oceanic and Atmospheric Administration maps suggest the presence of vast sand fields off Kahului Harbor, according to Cole.

Ocean sand in Hawaii comes from a variety of sources, including crushed up shells, certain kinds of algae, and fish such as uhu or parrotfish that eat coral for the polyps and excrete the calcium as waste, according to Norcross-Nuu. Sands from land-based materials, like black sand from lava rock, can also be added to the mix.

Not all sand is the same, and state laws require beach replenishment projects to closely match the type of sand added to the shoreline with the stuff found there naturally, Norcross-Nuu added.

The "Geotubes" proposed for the Stable Road project are intended to slow, but not stop, the migration of sand from east to west along the north shore of Maui.

The north shore beaches have been declining in recent years for several reasons, Norcross-Nuu said: Rising sea levels are increasing erosion, while offshore reefs are producing less sand; at the same time, development along the shoreline is locking up sand in inland dunes, and sea walls are preventing sand from being washed down shore, both stopping the natural replenishment of beaches.

Historical sand mining along the Spreckelsville-Paia coastline also contributed, she said.

According to the report to the BLNR by Dolan Eversole, a coastal geologist with the Department of Land and Natural Resources Office of Conservation and Coastal Lands, the seasonal sand movement along this beach "is very dynamic."

The beach has been retreating by a net average of 12 to 18 inches a year, according to the University of Hawaii Coastal Geology Group.

The goal of this project is to restore the beach to its approximate expanse in 1990.

A DLNR staff report to the board said the sand in the Stable Road project could last five to 10 years with the groins, or less than three if the groins are removed.

As the sand moves, it will help to nourish beaches to the west. There is easy access there, and people now reach the beaches in front of Stable Road (a private road) by walking along the shore from Kanaha Beach Park or the former Camp One.

If the renourishment works as expected, this lateral access will be improved. There is an old sea wall that now is sometimes touched by the high tide at the western end of the project area.

About 7,000 cubic yards of sand will be used to build up the beach, and another 3,000 yards will be piled up behind the vegetation line, to be mined by high waves to replenish the sand that waves wash away.

Guild says 20 years of trying various methods of restoring the Sugar Cove beach have shown that it is not so important where the sand is dropped. The ocean will move it anyway.

Although the Planning Department has a policy against any further armoring of beaches, the removable "Geotubes" are considered by coastal scientists about the most unobtrusive structures that could be put on a beach.

Norcross-Nuu said it is important with these groins that they extend far enough into the water that sand can move around their ends, and low enough that it can be washed over them.

The beach to be replenished is 900 feet long.

This is not the first project in the state to use dredged sand. The state did it at Kuhio Beach at Waikiki, and that project has been considered a success.

Harry Eagar can be reached at heagar@mauinews.com.