Think the Earth

The professional baseball season is about to begin, but in between seasons the Hanshin Koshien Stadium in Hyogo has been reborn as an eco stadium. The silver roof protecting the spectators from the strong summer rays and rain has been increased to 1.4 times the original size, to 7,500 square meters. The rain caught by the roof will be stored in 2 tanks (226 tons in total size), and then used for watering the grounds and for visitor toilets.

Some people in Japan say, "if you just let rain flow, it ends up creating a flood, but if you store it, it becomes a valuable resource." So facilities like the Tokyo Dome and the Saitama Stadium are already making effective use of rainwater. You can also use rainwater at home, too. Say that rainwater was stored on the rooftop of all houses in Tokyo prefecture. Then you would be able to store135 million tons of water. This is more than the water supplied to the Tokyo prefecture by the Yagisawa dam by the Tonegawa river system. Until now, the water administrators in major cities thought that building dams was the answer to water shortages, but if we could use rainwater stored at facilities and at homes in our daily lives, we can shake ourselves free from a life that is dependent on dams.

Using rainwater also contributes to preventing disasters. In large cities, much of the ground is covered by asphalt. That is why when there is heavy rainfall the rainwater cannot seep into the ground, and flows directly into the rivers, causing floods in urban areas. But if we can store water in tanks, these tanks will function as flood-control dams and help prevent floods.