Hitachi Construction Machinery


Kasumigaura Seiryusen (clear spring water pond)


Domestic wastewater from Hitachi Construction Machinery’s Kasumigaura Works is treated and turned into clean water, after which it is released into rice field irrigation ditches.

In April 2012, the clear spring water activities emerged out of a single comment from the general manager of Component Product Dept. I want to see if fish can live in this clean water. We converted a used stainless steel bathtub into a makeshift fish tank. The idea for an upright pump to carry water into the fish tank came from the workplace supervisor. Discarded electric wire reels and other items were used to make a vane wheel that rotates with the power of the falling water. From there, a vinyl hose was wound around the vane wheel from the ground up, to siphon water into the tank. The whole system was handmade from recycled items, without using money or a power source.

Employees were asked to submit names for the small pond. The name Kasumigaura Seiryusen (clear spring water pond) was chosen. Goldfish and the Japanese rice fish (medaka), which live in the pond, had babies, giving birth to a whole new ecosystem. During break time, some employees come to look at the spring and see how the fish are doing. We plan to affectionately watch over the living creates that inhabit this spring and monitor their growth.

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Kasumigaura Seiryusen (clear spring water pond)

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Handmade pump

The sign is also handmade from recycled materials!

∗ How we made the sign
Leftover chestnut wood was used. The letters were printed onto paper, which were pasted onto the wood. The letters were traced with a pen. We used a pencil to color in the backside of the paper to make it easier to see the letters. The paper is then removed and India ink was used to color in the letters.
We used white chalk to color the surface of the wood to prevent the India ink from running along the wood grain.

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Let’s see how big the fish have gotten!


A baby goldfish born last year

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A frog paid us a visit


Shijimi clams also live in the clear spring

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