The Reef Runway at Honolulu International Airport was the first major runway in the world built entirely offshore on an underwater fringing coral reef.
Planning for the runway began in 1967 to mitigate noise during aircraft takeoffs. The runway was planned as a preferential takeoff runway for heavy three and four-engine aircraft. Its offshore location insured that it would reduce noise levels around populated areas, as well as increase safety by changing flight paths away from downtown Honolulu area.
Studies for the project involved the use of three-dimensional hydrodynamic models to determine the runway’s overall effect on circulation patterns in the Keehi Lagoon, as well as wave forces on the structure. Tests were also made to protect the runway on the ocean side.
The final plan called for constructing the runway on coral fill. By the time it was finished more than 19 million cubic yards of dredged material had been used, pumped by three hydraulic suction dredges from four offshore borrow areas, to form the land mass. An additional 800,000 tons of quarried stone and 18,100 four and six-ton dolosse concrete armor units comprise the protective structure separating the runway form the ocean.
Great care was taken to minimize the environmental impact on surrounding areas, with the result that water quality was improved and provision made for the indigenous bird population of the region. The quality of water in the marine pond created by the runway was carefully considered by installing eleven 72-inch diameter culverts to allow for tidal circulation and mixing from the Manuwai Drainage Canal.
Other environmental protections included the construction of small islands in Keehi Lagoon for the Hawaiian Stilt, a rare and endangered species which could be affected by the impact of the construction. In addition, two large bird sanctuaries designed for the Stilt’s nesting were constructed in nearby Pearl Harbor.
Although the Runway was planned before Congress passed the National Environmental Policy Act of 1969, the project was one of the first airport facilities having to file an Environmental Impact Statement (EIS). The EIS was completed and approved in 1972, but environmental groups obtained a temporary restraining order to stop the project.
After going through three courts, and ending up on the doorstep of the U.S. Supreme Court, the runway EIS was ruled adequate, affirming the action of a lower court. The legal action stopped work on the runway for more than three months.
The Reef Runway structure is 16,100 feet by 2,050 feet, with the runway proper 12,000 feet by 200 feet. More than 1,000 acres of new land was created by the dredging of more than 19 million cubic yards of material. All dredged fill was placed in one to 30 feet of water. The circulation channels were dredged to -45 MSL.
The project was constructed in three phases:
- In Phase one, the Dredged Fill & Protection Structure was begun in May 1973 and completed in August 1976.
- Phase two was the pavement, Increment 1, which began in September 1975 and was completed in September 1976.
- Phase three was completion of the pavements and lighting, increment two. It began in November 1976 and was completed in September 1977. The work included completion of the taxiway pavements, paving of the runway and taxi shoulders, and installing the airfield lighting and navigation equipment.
The runway was completed and dedicated for use on October 14, 1977 at a final cost of $81 million.