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Debris from west Japan torrential rains posing problems for sea transport, fishing

Officials of the Kinki Regional Development Bureau pick up a piece of debris flushed into Hiroshima Bay by the recent torrential rains. (Photo courtesy of the Kinki Regional Development Bureau)

OSAKA -- The torrential rains that devastated wide areas of western Japan earlier this month washed a large amount of debris into the sea, affecting ferry services and fishing operations.

The Ministry of Land, Infrastructure, Transport and Tourism collected a total of 3,503 cubic meters of driftwood from July 8 through 21. This figure exceeds 70 percent of the amount salvaged in an average year, according to the ministry's Chugoku, Shikoku and Kyushu regional development bureaus. A ministry official said that debris is still flowing in from rivers, and "there is no end in sight."

The Chugoku Regional Development Bureau collected 913 cubic meters of debris adrift in the bay of Hiroshima. The 6th Regional Coast Guard Headquarters in the city of Hiroshima, which is in charge of the bay, is issuing radio and email warnings to shipping companies and others of the dangers of sea debris such as gas canisters and other ships. So far, 169 such advisories have been issued.

According to the Japan Coast Guard's fifth to ninth regional headquarters, which cover areas hit by the recent downpours, they have received no report of ships colliding with floating debris off the coasts of both the Kyushu and Kinki regions since the natural disaster.

But there have been cases of driftwood and other debris getting tangled up in ships' propellers and affecting their operations. One ship from the Shimanami Kaiun shipping company in the city of Mihara, Hiroshima Prefecture, was taken out of service after its propellers got caught in debris. The company suspended a nightly round-trip service on a route full of floating debris until July 19.

The Tsu Airport Line, headquartered in the city of Tsu, Mie Prefecture, also stopped its nighttime service connecting Tsu and the Chubu Centrair International Airport in the city of Tokoname, Aichi Prefecture, until July 18 due to driftwood floating in Ise Bay.

The debris is causing trouble for fisherman using fishing nets as well. In the city of Ozu, Ehime Prefecture, a large number of trees were flushed into the sea via the flooding of the Hiji River, rupturing dragnets along the shore. In Shimane Prefecture, large amounts of waste got stuck in stationary fishing nets. In Okayama Prefecture, debris was entangled in fishing boats' propellers or sucked into the intake for the water used to cool the engine.

In Nangoku, Kochi Prefecture, fishing ships belonging to a local fishing association have been facing difficulties in leaving the port to catch "shirasu," or whitebait, a popular staple of the area. Only two to three of the seven ships belonging to the association have been able to go to the sea because of debris in the port and on the beach.

The land ministry also issued warnings about debris that has stunk to the seafloor. According to the ministry's Chugoku Regional Development Bureau, large electric equipment such as refrigerators and other containers have sunken along the coast of areas damaged by the torrential rains. An official warned that the debris is difficult to spot compared to floating items, and may cause damage to a ship's hull.

(Japanese original by Koki Matsumoto, Osaka Science & Environment News Department)

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