### Disaster caused by flooding of Kumagawa River, Kumamoto Prefecture - July 2020

### Disaster caused by flooding of Kumagawa River, Kumamoto Prefecture - July 2020

In July 2020, a rainy season front stagnated over the Kyushu region of Japan, causing record-breaking rainfall in Kumamoto Prefecture. The Kuma River, which flows through southern Kumamoto Prefecture, overflowed due to the concentration of large amounts of precipitation in a short period of time, and the floodwaters flowed into the surrounding areas. In particular, areas such as Yatsushiro City, Kuma Village, and Hitoyoshi City were severely damaged, with homes and infrastructure flooded on a massive scale. On the day of the disaster, more than 500 mm of precipitation was recorded in a 24-hour period, making flooding of the Kuma River inevitable.

The flooding took the lives of 14 elderly residents of Senjuen, a special nursing home for the elderly in Kuma Village, before they could evacuate the facility. The facility is located along the Kuma River, and the rapid rise of the water level combined with the break in the levee to cut off the surrounding roads, causing a delay in rescue efforts, which in turn increased the damage. The Kuma River is a well-known sightseeing resource in Kumamoto Prefecture and an area with a rich natural environment, but this kind of torrential rain disaster once again highlighted the risks to the areas surrounding the river.

In response to this disaster, the Ministry of Land, Infrastructure, Transport, and Tourism announced a policy to invest a total of approximately 20 billion yen to strengthen levees and revetments along the Kuma River to promote flood control measures. In addition, Kyushu Electric Power Company, a local company, has expressed its cooperation in developing a real-time monitoring system for river water levels, considering the introduction of an early warning system using renewable energy after the disaster. Furthermore, Kumamoto Prefecture is strengthening evacuation drills for local residents and working with local communities to develop evacuation support plans for the elderly and disabled.

In addition, climate change is increasing the frequency of torrential rains, known as "linear rainfall zones," which is also adding to the increased risk of disasters. In particular, cases such as the flooding of the Kuma River indicate that conventional flood control infrastructure alone is not sufficient to deal with the situation, and there is an urgent need to further strengthen levees and establish systems to encourage early evacuation. Against this backdrop, there is a need for comprehensive disaster prevention and mitigation efforts through collaboration among the national government, local governments, and businesses.