Q: How should cities cope with downpours and floods caused by climate change?
A: Two wheels consisting of restrictions to keep the water retention of woods and drainage ability.
Fukuoka City experienced severe floods in the past, even the city centers flooded and disrupted the city function. With these experiences, the city government conducted a flood prevention project. And also having experience of drought in the past, the city is implementing the development of watershed protection forests.
Flood Prevention of Fukuoka City
Fukuoka City has developed as a major city with more than 1.6 million population, and it is important to keep the citizens safe and prevent the disruption of city function. The city experienced severe floods in the past, most recent ones in 1999 and 2003 flooded the city centers such as Tenjin and Hakata Station Areas. With these experiences, the city government conducted a project to prevent the third flood in the city.
In this project, the city government developed rainwater storage and permeable pavements in the city centers. The city developed a baseball ground near Hakata Station, which can be turned into a rainwater reservoir in case of heavy rainfall, and underground water reservoir was also built next to it, under a park. These reservoirs can keep 30,000 cubic meters of rainwater. In Tenjin Area, 7.7-kilometer network of huge drainage pipes with the maximum of five meters in diameter is being built in the underground due to the space limitation. In the completion of the network in 2026, 60,000 cubic meters of rainwater can be stored.
At the same time, the city government is developing watershed protection forests around the water sources of the city, that maintains and nurtures water resources and regulates river flow. Forest soil is porous like a sponge and has high water-retaining capacity. Therefore, it is possible to store a certain amount of water during heavy rainfalls, and keep the amount of water flowing into the river constant, preventing flood and drought. Pruning and adjusting the number of trees to create healthy forests are conducted. In order to spread the awareness of importance of these forests, the city government also regularly trains civic volunteers and partially subsidizes the maintenance cost to help the improvement of the forests.
In order to maintain the city function stable even in the case of less or too much rainfall, the implementation of the policy prepared for sudden climate change is important in the time when weather is unpredictable. and it is one of the requirements as the city serving as the administrative and commercial center of a region.
[Case ID: Urban Policy UP-06]