1953 North Kyushu flood

Updated on Dec 19, 2023

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The 1953 North Kyushu flood was the flood which hit Northern Kyushu, Japan (Fukuoka Prefecture, Saga Prefecture, Kumamoto Prefecture and Ōita Prefecture) in June 1953. The torrential rain of the rainy season, amounting to more than 1,000 mm on Aso and Hikosan mountains, produced the great flood to many rivers such as Chikugo River and the toll of more than 1,000 people dead and missing. 450,000 houses were flooded and 1,000,000 people suffered from the flood. The fundamental change of flood control in the Kyushu area was needed and the standards of flood control have been taken against further floods.

Name of the flood

The name of the flood remains unsettled. In Kumamoto Prefecture, Shirakawa Great Flood or 6.26 Flood is usually used, while the name of the flood differs from literature to literature. In Kitakyushu city, they use 「北九州大水害」,　or North Kyushu Great Flood. In the Japanese Wikipedia article,「昭和28年西日本水害」(1953, Nishinippon Flood) is used、based on the decision of the Western Japan Branch of the Japan Society of Civil Engineers. In this article, 1953 North Kyushu Flood is used, based on the areas of the flood.

Weather

In the early part of June 1953, a rainy season front (baiyu zensen) stayed in the middle of Kyushu causing heavy rain, which went southward to Amami Oshima. On the other hand, a Pacific anticyclone present in the Philippines pressed the rainy season front to the Tsushima Strait. At the same time, an anticyclone from China moved to Kyushu pressing the front to Yakushima. The rainy season front was pressed both from west and south, and stayed in the Mountain Aso around June 23, and the front was stimulated by the high temperature air from the anticyclones. Low-pressure areas passed in succession from Korea and Tsushima, which usually would have stayed in Yakushima.

In Kumamoto Prefecture, the central river Shirakawa flooded most severely, and people remember it by the name of 6.26 Suigai(flood). The factors of the 6.26 flood were: heavy rain in the Aso district(In Kurokawa mura), the rainfall reached 888.4 mm in 5 days, another factor being the soil of the areas; it contained layers rich in yona(volcanic ash) over lava; which easily liquefies on heavy rain.

A similar event was seen in 1993 Kagoshima Heavy Rain. .

On April 27, Mount Aso erupted and a great amount of volcanic ash which fell was mixed with rain; producing peculiar debris flow in the Kurokawa river and Shirakawa river merging into Shirakawa into Kumamoto.

The third factor was the Kumamoto city; the river Shirakawa was the so-called tenjo-kawa, or a ceiling river, namely, the river bed is higher than its surroundings such as Shimotori. These factors worsened the damage of the flood.

70% of the then Kumamoto city was flooded, except the Kyomachi Hills and Kengun area. The central areas of Kumamoto City were 2.5 meters to 3 meters deep in muddy water. 15 bridges out of 17 in the city were carried away except Taiko Bridge and Choroku Bridge. Kokaibashi was carried away with 40 inhabitants.

The disposal of 60,000,000,000 tons of muddy soil presented big problems; 116 areas including a moat of the Kumamoto Castle were used. The Kumamoto city gave subsidies to clean up the streets; 2000 yen for bicycle trailers, 4500 yen for 3-wheel cars and 10,750 yen for a truck; producing many small enterprises with trucks.

A house for the aged was destroyed and 52 people were killed.

The damage amounted to 17,300,000,000 yen (121,930,000,000 yen,now)

Even in the southern part of Aso gun, the dead and missing amounted to 66.

Shirakawa Suigai in Japanese

Flood in Fukuoka Prefecture:Chikugogawa Area

The Chikugo River (筑後川, Chikugo-gawa) flows through Kumamoto, Oita, Fukuoka and Saga prefectures in Japan. With a total length of 143 kilometres(89 mi), it is the longest river on Kyushu. It flows from Mount Aso and empties into the Ariake Sea. The river is important to industry, with twenty electrical power plants located along its banks, as well as the major city of Kurume in Fukuoka Prefecture.

147 people were killed in the areas of Chikugo River; all areas of Tsukushi plain were flooded, and the Yoake dam which was under construction, the bank of Kasegawa, and the bank of Yabegawa, the area of Homan Gawa were also flooded. 80 percent of Kurume city was flooded; in the center of the city, water was 1 meter deep, 3 meters deep at the deepest. This flood is called one of the three worst floods, including that of 1890 and that of 1921.

The total damage amounted to 79,300,000,000 yen, which was equivalent to twice the yearly budget of Fukuoka Prefecture.

Damage

The Japanese Government took appropriate measures comparable with those took for typhoons in 1948. The 5th Yoshida Cabinet (Government) placed " Nishinihon (West Japan) flood countermeasure center" in Fukuoka City. Not only National Safety Forces(which later became Land Force), but also American soldiers helped. The people in the flooded areas greatly appreciated the supply of free food and water, while they thought the flood was a natural disaster and could not be helped.

Countermeasures

1953 was the year of great disasters; the heavy rain in the south Kishu area, Wakayama Prefecture, with 1,046 people dead and missing and in the Minami Yamashiro area(105 people were killed). The causes were attributed to reckless deforestation, and the lack of water control after the second world war. The damaged Yoake Dam was investigated but the inadequate water control of the upper river was found to blame. The Japanese Government decided to follow America and its Tenessey Valley Corporation and started to build many dams such as, Matsubara Dam, Shimauch Tsutsumi (Chikugo River), Shimouke Dam (Tsue River), Ooishi, Harazuru, Sennenbunsuiro (Chikugo River), Chikugoooseki, Terauchi Dam (Sa ta River), Ishiharagawa Dam, Ooishi Dam, Jouharagawa Dam, Hyugakami Dam, Masubuchi Dam, Aburagi Dam, and Jin-ya Dam. In 2009, the countermeasures were again under review in view of the global warming and heat island phenomenon and the outbreaks of heavy rainfall in Northern Kyushu in 2009.

References

1953 North Kyushu flood Wikipedia

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