Ancient Cooling

Humid summer sun…

The pores of the city clogged

With our human sweat –

You deftly sprinkle water

Cool our streets and cleanse our sins

This is a Tanka, inspired by recent research that has identified the ancient Japanese tradition of uchimizu as an effective way of combatting the urban heat island effect.

Uchimizu involves the sprinkling of water over an area of land (uchi comes from the Japanese verb utsu meaning to hit or strike, and mizu is the Japanese word for water), and it is traditionally performed using a bucket and ladle whilst wearing a yukata. The urban heat island effect is when an urban area is found to be significantly warmer than surrounding rural environments because of human activities. Researchers working at TU Delft in the Netherlands investigated if the practice of uchimizu reduced the urban heat island effect by creating a three-dimensional cube filled with fibre optic cables. After throwing water over the measured area, the fibre optic cables were then used to see if the ground and surrounding air became cooler. The researchers found a positive result, concluding that the practice of uchimizu reduces the initial surface temperature of the ground and leads to a cooling effect for the surrounding air.

This research was presented at the European Geosciences Union 2017, and by mitigating the urban heat island effect, this simple and ancient tradition has the potential to decrease extreme temperatures in urban environments.

An audio version of this poem can be heard here.