Two-way Drainage Mill
Two-way milling was unique in the world
Overwaard windmill number 4 was the only one of its kind in the entire world. No other mill was capable of milling the water in two directions. It all becomes even more impressive when you consider that there was no intricate plan to underpin the two-way drainage mill’s construction: they had to improvise it all ‘on the go’.
The decision to fit Nederwaard windmill number 4 with two scoop wheels instead of just the one was taken in the 30s of the eighteenth century, after another mill burned down. This caused a serious and immediate lack of drainage capacity. On July 17, 1739, the eight windmills of the Overwaard quay were commissioned. Just two weeks later, a polder windmill that was already located at the Overwaard was lost in a fire. Rather than reconstructing this mill, it was decided that the fourth mill at Overwaard would get an overhaul, featuring twin scoop wheels capable of draining the high basin in summer. This was a much cheaper solution.
The mill’s history can be divided into two periods: two-way drainage mill (1740 – 1800), and basin drainage mill (1800 – 1950). In the dual scoop wheel period, the miller only had a tiny bit of space left to live in. After the second scoop wheel was removed by the end of the eighteenth century, the space was enlarged and used as a living room. All other mills in Kinderdijk have only one scoop wheel. The second wheel allowed the two-way drainage mill to drain the water out the Overwaard Upper Basin. This in turn opened up the drained land for use as cattle pasture.
The Upper Basin consists of meadows enclosed by dikes, which still features visible ditches and vegetation. The raising of dikes around the basin marks an important moment the history of the District Water Board. At the time, the fertile pastures were not just intended for water storage, but also for cattle farming. The miller responsible for this area was paid more than his colleagues because he had to make sure the Upper Basin remained dry throughout the summer while the other millers had easier jobs.