Ban Bo Waterwheels

A flute sounds across a valley in Tam Đường, in Lai Châu, and no one is playing it.

The sound comes from the Nậm Mu stream, where it runs past the village of Nà Khương. Long before anything comes into view, a low, even rise and fall drifts through the valley, like a bamboo flute. It is made by 35 waterwheels turning on the water, each with bamboo tubes fixed to its blades. As a wheel turns, its tubes move through the air and make that sound.

That is 35 waterwheels along one stretch of stream. It is described as the place with the most waterwheels in the Northwest of Vietnam.

These wheels are not a model built for tourists, and they are not copies made for photographs. They work every day, doing what they have been made to do for hundreds of years: lifting water from the stream up to the fields.

The principle is simple. The fields at Nà Khương lie higher than the stream, so an ordinary channel cannot bring water to them. The Thái people here found another way. The Thái are one of Vietnam's ethnic groups, and Lai Châu is one of the provinces where they mainly live. They built wooden wheels and set them in the stream bed, with the blades dipping into the running water. The current turns each wheel. Along the blades are fixed tubes of bamboo or nứa, and as the wheel turns, every tube scoops up water from the stream. At the top of the turn, the water tips out into a trough that carries it off to the field.

No electricity is needed. No pump, and no fuel. All it takes is a flowing stream. As long as the water runs, the wheels turn, at no cost and with nothing used up.

The Thái worked this out a very long time ago. The method is so simple that a child could be taught it, yet it works so well that the people here have not needed to change it in hundreds of years. The design is simple and clever at once.

A waterwheel is made of wood, rattan, bamboo and trúc, all taken from the forest around it. Nothing is ordered from a city, and no special material is needed. When an old wheel breaks, people cut trees in the forest and build a new one. The materials go round in a closed circle, in step with nature.

The finest season at Bản Bo is September and October, when the rice on the terraced fields ripens to gold. Then the 35 wheels turn steadily in front of the glowing yellow terraces, a view that many photographers have come back to more than once. In May and June, when water floods the fields, the terraces turn green and the reflections are beautiful in a different way.

Small huts near the stream bank serve Thái food. There is grilled stream fish, cá suối nướng, and sticky rice, xôi nếp. There is also grilled stream moss, rêu nướng. All are simple dishes from fresh local ingredients. In the early morning, the first sunlight comes down onto the wheels and the terraces.

Bản Bo is not a loud place. The wheels turn, the bamboo tubes call like flutes, and behind them the terraces ripen to gold.