Kai Tak Airport

 - August 11, 2008, 6:16 AM

Though the former Hong Kong International Airport–Kai Tak–closed on July 5, 1998, its passenger terminal, control tower and hangars remain in ad hoc use, ranging from flea markets to a job-training center, and now, on the runway, the world’s largest golf driving range. All that remains of Kai Tak will be bulldozed by
year-end to make way for a new station for Mass Transit Railway, and over the course of the next 15 years, some 260,000 Chinese government housing units. Kai Tak Point, at the threshold of former Runway 31, may eventually include a 50,000-seat stadium, two hotels, a hospital, 28 schools and a cruiseship terminal.

While plans are ambitious, economic woes have delayed most building in Hong Kong, and no one yet guarantees the land is safe for use. A taxiway bridge to the south apron built in the early 1970s had formed a bucket of toxins. At least 100 tons of aviation fuel leached into Kai Tak Approach Channel, which also collected industrial metals such as chromium, mercury and zinc, in addition to volatile organic compounds such as polychlorinated biphenyls (PCBs).

Remediation work was stalled for “rescue excavations” of items of archaeological importance, since the area has been settled from the Han Dynasty in 206 B.C. Dredging was kept to days thanks to kind winds and temperatures, but methane gas seeped to underground garages and elevator pits. Engineers then staked out 2,000 soil vapor-extraction wells at waist height, resembling a vast drive-in. By the end of last year nearly 1.1 million cubic yards of methane gas had been burned with little effect on “noise sensitive” or “odor sensitive” people or to fish, mainly because most fish were long dead. “The Kwun Tong port survey recorded no adult fish and fry production from the Kai Tak area,” declared Hong Kong’s Legislative Council.

The new Hong Kong Chek Lap Kok International Airport (CLK) is subject to more dangerous wind shear than its predecessor, though one of the world’s most advanced warning systems and generous room for navigation allow some latitude. Hong Kong weather is devilish at any location, as severe thunderstorms frequently prevent flight operation.

Like its predecessor at Kai Tak, the new Hong Kong International off Lantau Island is built on dredged mud reclaimed from the Pearl River Delta and South China Sea. Five years after its opening, the airport is sinking from the weight of its mile-long concourse, 68 escalators and 10,400 luggage trolleys. Dr. Xialo Ding of the Hong Kong Polytechnic analyzed satellite synthetic aperture radar interferometry to conclude that CLK has already sunk 50 mm (a fifth of an inch).