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Studies of the flood damages caused by heavy rainfall

1970; Society of Agricultural Meteorology of Japan; Volume: 25; Issue: 4 Linguagem: Inglês

10.2480/agrmet.25.257

1881-0136

Tsutomu SAKANOUE,

Cryospheric studies and observations

The agriculture in Japan, especially in western Japan, suffers from flood damages.In this paper the author investigated the property of the heavy rains during the period from 7th to 10th of July 1967, recording the total amount of precipitation over 300mm in the north-western Kyushu, including the region of Nagasaki and Saga prefectures. Many severe flood damage landslides and their related damages occurred owing to the rainfalls.The results of the investigation from the standpoint of the local scales are as follows:(1) The heavy rains are composed of concentrated heavy rain caused by mesoscale disturbances passing along the Baiu front and of that associated with a low pressure.(2) The rain area is composed of 3 zones which stretched out from western Nagasaki to the Seburi mountains. The scale of rain cells (area) is about 10 to 20km in diameter and their intensity are at most 20-40mm per 10min.(3) In the later part of this paper, the author makes a survey of landslids, and occurrence of landslide related to the rainfall. The author suggests that the landslides are more closely related to heary rainfalls of 20mm/10min than hourly and daily rainfall.