The people of Yuraj Molino (“white mill�) live surrounded by wheat fields, in a large valley near the small town of Pocona, Bolivia. As the name suggests, there have been flour mills in Yuraj Molino for some time. But by the late 1970s, customers were complaining of how long it took to grind the wheat; they got tired of waiting all day for their flour. And then millers began to notice that with the warmer, dryer climate, the streams no longer carried as much stream water, to power the mills. Some of the mills closed. Ana and I visited the ruins of a miller’s house, the yard full of weeds, with the mill still there and a calendar for 1984 still on the wall.

Other mills survived. Local miller Juan Torrico showed us his old mill house, with the canal that once brought water from the mountains. In 2001, Juan’s brother Sergio designed a new mill at the mill house. He bought two large, new stones from a master craftsman near Epizana, Cochabamba, who still carves the massive limestone wheels. Sergio bought a diesel engine, and a used truck axel. The brothers built a new mill house and mounted the stones in it, fixed the axel upright below them, and then used a steel rod to connect the axel to the diesel engine, which Sergio put in the next room. This way they kept the diesel smoke and the engine noise out of the mill room. They don’t want the smoke to spoil the delicate flavor of the flour, which people love.

Five or six other mills in the valley are also sited where old water mills used to be, near running water. But most of them are also now powered by diesel motors.

One by one the old water mills around Pocona adapted to diesel, and one or two are still using water power. The change to diesel was gradual and there was never a break in service, never a time when the farmers had no mills to go to. The mills themselves also stayed in the same places. Although the mills were originally sited to be near water, they were also near the wheat fields, and the millers owned the land where their mills were, and they had community ties to the area. So, the diesel mills stayed right where the water mills had been.

There is no research institution providing expertise on how to motorize Bolivian water mills. At some point, the millers themselves had to blend their traditional knowledge with a lot of new information about motors and old truck parts. As always, people in rural areas are constantly creating and making sophisticated adaptations to changing conditions.