Japan, US mull $4.5 bn floating runway

TOKYO, Sunday (Reuters) - Tokyo and Washington are considering building a giant floating runway off southwestern Japan in an effort to reduce noise pollution caused by U.S. forces' night exercises, a national daily said on Sunday.

The two countries aim to include the idea in an interim report, to be drafted in October, on realignment of the nearly 50,000 U.S. troops based in Japan, the Yomiuri Shimbun said.

The U.S. military wants to move about 70 fighter jets to the facility and hopes use of the "megafloat" will help it win over local residents to the idea, the newspaper said.

Reports of crimes committed by American servicemen, along with noise and environmental pollution, mean U.S. military bases are unpopular neighbours with many Japanese.

The megafloat, which wouldcost up to $4.5 billion, would be built about four km (2.5 miles) away from an existing U.S. marine base at Iwakuni in Yamaguchi prefecture, on the southwestern end of Japan's main island, Yomiuri said.

Washington also wants to relocate some exercises now carried out on the remote island of Iwojima to the new floating runway, the report said.

The megafloat would be made of hollow metal boxes and have an estimated lifespan of 100 years, it added.