Abukuma River “Biggest after the war” 33 years ago Greatly exceeded flood flow Typhoon 19 October 18 19:52

In the Abukuma River, where large-scale flooding occurred in succession due to typhoon No. 19, the flow rate from late night to early morning on the 12th of this month was said to be the largest after the war in almost the entire basin in Fukushima Prefecture. It turns out that the flood of 61 years was greatly exceeded. The country uses the flood in 1986 as a standard to prevent inundation damage, and its policy is to investigate in detail the causes of flooding and flooding at that time.

The Abukuma River maintenance plan formulated by the Ministry of Land, Infrastructure, Transport and Tourism assumes the same flow rate as the August 1986 flood, which was said to be the largest flood after the war, and expanded the river width to prevent inundation damage. And the development of embankments.

According to the Ministry of Land, Infrastructure, Transport and Tourism, an estimated flow rate of 4900 cubic meters per second was set at the observation point in Fukushima City in 1986. In the meantime, we found that it had reached 5000 to 6000 cubic meters per second.

At 3:00 am on the 13th, we observed a maximum of 6010 cubic meters per second.

In addition, there is no expected flow rate at the observation point in Motomiya City where seven people died, but we observed 4067 cubic meters, the maximum at 3am on the 13th, compared to 3403 cubic meters per second during the August 1986 flood. .

In Fukushima Prefecture, it was found that almost all of the basin was observing a flow rate that exceeded the largest flood after the war, and it was possible that the flooding was a widespread factor.

According to the Ministry of Land, Infrastructure, Transport and Tourism, the observed flow rate is a tentative value.

Rainfall in Fukushima Prefecture 2 to 3 times that of the first month of October

The factor that increased the flow of the Abukuma River was the rain that continued to fall in the basin, and the rainfall in Fukushima Prefecture reached two to three times that of October 1 of the normal year.

The rain began to fall on the 11th of this month, with a rainfall of 24 hours, ▽ 441 mm in Kawauchi Village,
▽ It is 371 mm in Shirakawa City near the water source of the Abukuma River, and it has become the largest since we started collecting statistics at 14 observation points near half of the prefecture 31.

On the other hand, only one spot observed very heavy rain of 50 mm or more per hour, and in many areas it was raining 30 to 20 mm per hour.

The Japan Meteorological Agency analyzed that rainstorm clouds rarely developed locally in Fukushima Prefecture, but a large amount of water vapor continued to flow for a long time due to a large typhoon, which may have resulted in record rainfall Is proceeding.