Posted on: Tuesday, November 6, 2001

Deep-sea portion of Keahole pipeline in place

By Jan TenBruggencate
Advertiser Science Writer

Contractors have installed the seafloor portion of a massive new shoreline-to-deep sea pipeline off the Hawai'i Ocean Science and Technology Park near Keahole Point on the Big Island.

The high density polyethylene pipe is 55 inches in diameter and runs from 500 feet offshore to a point 9,700 feet offshore and 3,000 feet deep.

It is designed to provide clean, nutrient-rich water from the deep ocean to the commercial businesses at the 547-acre industrial park operated by the Natural Energy Laboratory of Hawai'i.

The water comes up at 37 degrees Fahrenheit and can be pumped at 27,000 gallons per minute.

The system is expected to provide cold seawater to customers beginning in July.

Healy Tibbitts Builders assembled and installed the nearly 2-mile-long pipeline from 60-foot lengths of pipe.

It was towed Oct. 5 from Kawaihae Harbor and installation was completed Oct. 12.

The pipe was floated to Keahole full of air, with its concrete anchors in place. It was flooded to let it sink.

Delays were encountered because of broken hawsers and strong currents.

Remotely controlled unmanned submarines were used to assist in the deployment, and to survey the completed installation for trouble.

The pipe is being connected to shore through previously constructed tunnels that cross the shoreline. A surface seawater intake structure also was recently installed.

Pump structures and distribution systems still must be built. Natural Energy Laboratory scientific and technical program manager Tom Daniel said the entire project is payed for through roughly $21.5 million in state capital improvements money, and most of the tenants of the technology park will use the water for aquaculture.