EDITORIAL | Lesson from Noto Rains: Flood Control Should Be Top Priority

One month has passed since record-breaking rains hit the Noto Peninsula region in Ishikawa Prefecture. Fourteen people died in the frequent floods and landslides that followed, and others are still missing.

In addition, around 400 people are still living in evacuation shelters. And the road to recovery and reconstruction will be a difficult one.

Unfortunately, the heavy rains hit the same areas affected by the Noto earthquake in January. Since then, more than 1,400 homes have been damaged due to flooding and other causes. Moreover, water and power outages continue in some areas.

There is concern that the health of residents will be adversely affected by the continuing conditions. Accumulated fatigue, stress from being evacuated for an extended period, and cleaning up their devastated homes take their toll. Now the cold weather season is approaching. Local and national governments must provide all possible mental and physical support for Noto residents to rebuild their lives.

*An aerial view of the flood zone a day after the heaviest rains on record in Wajima, Ishikawa Prefecture (Afternoon of September 22)*

Flooding Small, Medium Rivers

The flooding of local rivers in a short time caused much of the extensive damage. Since the water levels of small and medium-sized rivers can rise suddenly from heavy rain, the risk of delayed evacuations becomes elevated.

Prefectural governments are responsible for managing many small and medium-sized rivers. However, since their surveys and networks of observation stations are insufficient, they have difficulty predicting water levels and the risk of flooding. They also lag in the creation of hazard maps. The national government needs to support greater efforts to share risk information with residents and encourage early evacuation.

It has also been pointed out that the earthquake may have weakened the ground, causing landslides and flooding to worsen. It is important to conduct surveys from the perspective of such complex disasters.

Flooding also occurred in temporary housing built after the earthquake. Due to the lack of level land, these facilities had to be built in places with a risk of flooding. However, the propriety of this decision should now be reevaluated.

*Driftwood washed up on homes and shops in the aftermath of the heavy rains and flooding on September 21, in Wajima City, Ishikawa Prefecture*.

The Global Warming Factor

Large-scale floods have been occurring frequently in recent years. The underlying reason is an increase in rainfall due to global warming. By one estimation, if the global average temperature rises by two degrees compared to preindustrial times, the frequency of flooding in Japan will double.

For this reason, the government is revising its river improvement plans, which were originally based on past rainfall levels. Instead, it is creating plans based on projected future increases in rainfall.

However, river improvement work, such as building levees and digging riverbeds, will require huge outlays. They also take decades to complete.

Construction work based on these new plans has yet to begin. Furthermore, there is concern that it will not be able to keep up with the worsening flood damage. Therefore, the government should continue focusing on accelerating river control projects and allocate the necessary funds.

Floods, like earthquakes, can occur anywhere in Japan. There is an urgent need for the national and local governments and the general public to come together and take action.