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Uchimizu - Bring Coolness to the Japanese Summer

While returning home in the late afternoon one summer’s day, Raoul bumps into a neighbor, Kikue-san, who is accompanied by her granddaughter Hatsune-chan. The two have just come outside, and they are carrying a pail and a ladle.

Uchimizu - Bring Coolness to the Japanese Summer

Kikue

Hello there Raoul, welcome home.

Raoul

Kikue-san, Hatsune-chan, what are you doing with a pail full of water and a ladle?

Hatsune

Well my grandmother and I are about to do uchimizu.

Raoul

Uchimizu

Kikue

Uchimizu is the spreading of water throughout gardens and on the roads in front of homes. As a way of enduring the summer heat, it is a piece of wisdom that has been handed down to us from the Edo Period.

Raoul

I see! The evaporation of the water that has been spread about takes away heat from the ground, and that in turn reduces the ambient temperature in the immediate vicinity.

Kikue

That is correct. What is more, when doing uchimizu, it is said to be more effective if done during times of the day when the evaporation process occurs more slowly. In other words, it is more effective in the morning and evening when the temperature is not so hot.

Raoul

Yes, I can appreciate that idea. If you were to spread water on ground exposed to the blazing sun, I don’t think it would be very effective because it would immediately evaporate away. It seems that doing so would also raise the humidity and make it unbearably steamy.

Hatsune

Hey, why don’t we spread the water together? I’ll give you my ladle.

Raoul

That’s very nice of you Hatsune. OK, please give me a try. This is good! Just spreading the water is relaxing, it also makes me feel pleasantly cool.

Kikue

Yes, I agree with you! As to the practice of uchimizu, along with the paving of roads, and the adoption of fans and air conditioners in the home, it has tended to disappear little-by-little over time. However, as a way to respond to the heat island effect, in recent years uchimizu has experienced somewhat of a resurgence in interest.

Raoul

The heat island effect is something that is being experienced by cities around the world. Here in Japan as well, commencing with Tokyo it has become a serious issue for a number of places.

Kikue

That is true. That is why trials have been carried out of everybody engaging in uchimizu at once in order to reduce the temperature of road surfaces as a means by which to lower the temperature of cities that are experiencing the heat island effect. This social experiment named the “Great Uchimizu Campaign” was started by Tokyo in the summer of 2003. Now it has grown into an annual event that takes place during summer in various regions across Japan.

Raoul

The “Great Uchimizu Campaign”! That has an amusing ring to it!

Although Raoul has expressed an interest in the Great Uchimizu Campaign, it seems that he has one concern.。

Raoul

Hold on, if everybody does uchimizu together, wouldn’t that require a great volume of water? If that is the case, my interest would wane.

Hatsune

Don’t be worried! Doing uchimizu as part of the Great uchimizu Campaign means utilizing water that is being reused.

Kikue

That is correct. The rule is that you are not supposed to use tap water, but rather rain water or water that has been used for some other purpose. For example, water that is left in the bath tub, or the water that remains after doing the dishes. There is also water that has been used to fill children’s paddling pools, or water that is generated by the outdoor convection units of air conditioners.

Raoul

Hearing that puts my mind at ease. By the way, how do we participate in the Great Uchimizu Campaign?

Kikue

Well one way is to take part in the events that will be organized in different regions by local municipalities, town associations and shopping streets, etc. Another option would be to get together with family and friends and do uchimizu somewhere convenient.

Raoul

If that is the case, I think I will organize something with my university friends. I’ll hook up with them now over SNS. Then again, what should I do about a pail and a ladle?

Hatsune

You don’t need to worry about that. It is good enough just to fill up a bucket or a bowl and then splash out the water with your hands!

Raoul

I see. The good thing about the Great Uchimizu Campaign is that anybody can participate in a relaxed frame of mind.

Hatsune

I’d like to splash around the water as well with you and your friends.

Raoul

Of course, of course! I will invite you as well, please be patient.
■The Great Uchimizu Campaign 2017
http://uchimizu.jp/ (in Japanese only)