Posted on: Tuesday, June 26, 2001
Plan to fortify Tern Island revealed
By Jan TenBruggencate
Advertiser Science Writer
The U.S. Fish and Wildlife Service hopes to wrap Tern Island in rock and steel to prevent it from washing away.
The rusting steel plates that for 50 years have held together the largest island within French Frigate Shoals are collapsing and threatening the erosion of the island.
Tern Island was an 11-acre sand spit when the U.S. Navy expanded it, establishing a rectangle of steel plates pounded into the reef and filled with coral debris. The work created a mid-ocean runway 3,000 feet long and covering 34 acres.
The Navy left after World War II and the Coast Guard moved onto the island in 1952 to establish a Long-Range Aids to Navigation station.
The Coast Guard turned the island over to the Fish and Wildlife Service in 1979, and the service since then has staffed Tern with a small cadre of biologists who keep tabs on millions of sea birds, turtles, seals and other wildlife within the Northwestern Hawaiian Islands National Wildlife Refuge.
Rust and a half-century of storms have destroyed many of the steel plates that protect the north, east and west side of the island, and others are near failing.
A channel through the reef was built by the Navy, and it has increased current flows around the island. Without protection, Tern Island would likely entirely wash away, the service said.
The Fish and Wildlife Service has prepared a draft environmental assessment on a proposal to reconstruct the protective barriers.
Its preferred alternative is to install 820 feet of new steel sheet pile at the western end of the island. The steel would have concrete caps above the waterline to minimize corrosion. Additionally, 3,854 lineal feet of shoreline would be protected by a rock revetment with a sloping face. The rock would have to be imported because the coral atoll has no quarry source.
The southern side of the island is not subject to erosion, and would have no new construction.
If financing for the full project is not available, the service has alternatives with less protection.
While construction crews would need to be on the island for up to two years, there would be measures to minimize the impact on nesting wildlife.
The service is seeking public comment by Aug. 15 on the draft environmental assessment. Copies are available at public libraries and at the offices of the Hawaiian/Pacific Islands National Wildlife Refuge Complex, 300 Ala Moana Blvd., Room 5-231, Box 50167, Honolulu HI 96850. For details call 541-1201.
