The Problem of Flooding in Japan and Solutions

The Problem of Flooding in Japan and Solutions

The year 2019 showed how susceptible Japan is to natural disasters. Flooding, which is still one of the worst natural disasters, is a problem that the country has to deal with almost every year. In 2018, too much rain in western Japan caused flooding and landslides, which killed at least 175 people, forced millions of people to leave their homes, and led to the disappearance of dozens more (Yoshida et al., 2022). This was the worst weather disaster to hit the United States in the recent 36 years. The remains of Typhoon Prapiroon were part of a rainy weather front that was caused by warm air from the Pacific Ocean (Ishiwatari, 2020). This pattern is the same as the one that caused flooding in southern Japan a year ago, killing dozens of people. The recent rainstorm was unusual, and experts on natural disasters worry that severe rains are becoming more common, possibly because of global warming. For the whole year of 2019, flood damage in Japan is expected to cost 2.15 trillion yen (Japan Government, 2021). In 2021, floods caused more damage across the country than they did in 2020. Flooding from rivers and other bodies of water, overflowing drains and sewers caused by heavy rain, storm surges, tsunamis, debris flows, and landslides all added to the damage. Except for years when a huge tsunami hit Japan, the average amount of damage caused by tsunamis each year in 2018, 2019, and 2021 was the highest it has ever been.

The first solution for Japan’s long-standing issue of flooding is the construction of underground reservoirs utilizing modern technology. For Japanese cities that lack green spaces to develop proper rainwater catchment technologies, the proposed solution will use special sheets made out of polypropylene sheets and channel devices that would line the underground reservoirs as opposed to river stones (Huang, 2014). In this solution, the idea is to hold the rainwater that is discharged into rivers and large water bodies causing flooding. Through the usage of this technique, it would be simple to construct subterranean reservoirs. When compared to stones or concrete tanks, the polypropylene sheets and channeling systems are far more manageable in terms of weight and portability.

As a second solution, flood control measures are now being put into place at Shibuya Station, which is one of the most well-known and frequently visited tourist locations in all of Tokyo and an area that is also highly susceptible to flooding. The system implemented in such spaces will also be duplicated elsewhere. In this solution, the main problem is that the earth that surrounds the station is lower than the terrain that makes up the rest of the area (Taki, 2022). As a result, the underground shopping malls and other establishments in these lower areas have a history of being susceptible to flooding. However, as part of a broader redevelopment project in the region, a brand-new rainwater storage tank with a capacity of 4,000 cubic meters was recently finished and went into service in August 2020 just below the station’s east exit (Taki, 2022). If there is an unusually large amount of rain, it will temporarily store the water and then, after circumstances have returned to normal, it will let the water to flow out through the sewage pipes. This will happen only if the amount of rain is very high. The same system is expected to be implemented elsewhere as a way of ensuring that rainwater is not destructive through flooding.

Adding to the solutions proposed and presented herein, I tis important to note that people in every region of Japan are adopting extra safety measures in order to protect themselves from the impending floods. The construction of levees and detention basins is one of these measures, as is making it easier to predict when it will rain hard (Fan and Huang, 2020). Other strategies include: Dams in Japan serve several purposes, including the generation of hydroelectric power and the irrigation of land, but their primary function is to avoid flooding. As part of its preparations for the Olympic and Paralympic Games to be held in Tokyo in 2020 and beyond, Japan is making progress toward developing a national land infrastructure that can resist the impacts of natural catastrophes. The measures were implemented as part of the preparations for the Olympic and Paralympic Games to be held in Tokyo in 2020 (Yoshida et al., 2022). It is proposed that similar initiatives including building of levees and detention basins. Dams are also in the proposed solutions for cities, done in a style that will enhance the beauty of cities in parks and other areas that already have the infrastructure for enabling such solutions.

A final solution proposed for Japan’s cities is the Underground Discharge channel that begun operations in 2009 in Tokyo (Yoshida et al., 2022). The system has so far helped Japan’s capital to reduce the effects of heavy rains and flooding. Therefore, it should be implemented in other cities to have the same results. The discharge canal is the largest structure of its kind anywhere on Earth. It is used to move underground floodwater. Five of Tokyo’s rivers drain into the underground canal through drain tunnels that go straight up. A large underground reservoir is connected to the surface by an underground tube called. When it rains a lot, this tube is used to catch the extra water. When the storm is over, the water in the reservoir will be poured into the receiving river. When it is not completely under water, the underground tube is a popular place for tourists to visit, thus also enhancing revenue for the city. It has also been used as the setting for a number of movies and TV commercials. Such solutions add value to the entire process, a phenomenon that can be replicated in other flood-prone areas in Japan.

In conclusion, since flood control measures such as the Outer Underground Discharge Channel in Metropolitan Areas and the Underground Regulating Reservoirs built in urban areas were put into place, there has been a significant reduction in the amount of flooding and property damage caused by heavy rain. It is quite unusual to see standing water on the streets of cities such as Tokyo, even after a significant rainfall. This is due to the fact that the city is guarded by a great deal of infrastructure that is buried beneath and cannot be seen. The fact that it does not typically rain much in Tokyo is the primary factor in this phenomenon. It is probable that these technological advancements will continue to assist in protecting Tokyo for a good number of years to come, even as the city continues to adjust to the shifting weather patterns. The proposed solutions in this discussion further point to a need to ensure that measures such as utilization of spaces under bridges and roads are used effectively to prevent flooding. 

Reference List

Fan, J. and Huang, G., 2020. Evaluation of flood risk management in Japan through a recent case. Sustainability, 12(13), p.5357. Viewed May 24 2022,

Huang, G., 2014. A comparative study on flood management in China and Japan. Water, 6(9), pp.2821-2829. Viewed May 24 2022,

Ishiwatari, M., 2020. Evolving Concept of Resilience: Soft Measures of Flood Risk Management in Japan. Connections (18121098), 19(3). Viewed May 24 2022,

Japan Government. 2021. Utilizing the City’s Underground Spaces to Prevent Flood Damage. Viewed May 24 2022,

Taki, K., 2022. Flood Management Policy in Shiga Prefecture, Japan: Implementation Approach of a Risk-Based Flood Management System at Catchment Scale. In Green Infrastructure and Climate Change Adaptation (pp. 43-59). Springer, Singapore. Viewed May 24 2022,

Yoshida, S., Kashima, S., Ishii, S., Koike, S. and Matsumoto, M., 2022. Effects of the 2018 Japan Floods on long-term care insurance costs in Japan: retrospective cohort study. BMC public health, 22(1), pp.1-11. Viewed May 24, 2022,,destroyed%20%5B8%2C%209%5D.