http://www.amusingplanet.com/2014/11/the-windmills-of-kinderdijk.html The Windmills of Kinderdijk By Kaushik Wednesday, November 05, 2014 The village of Kinderdijk is located in the Netherlands, about 15 km east of Rotterdam. Kinderdijk is situated in a region called the Alblasserwaard that lies below sea-level. Called polders, these regions are often land reclaimed from a body of water, such as a lake or marshes. After the water is drained out of the water bodies, the ground level subsides over time and eventually all polders sink below the surrounding water level. Water then enters the low-lying polder through water pressure of ground water, or rainfall, which has to be regularly pumped out or drained by opening sluices at low tide. In Kinderdijk, most of the water originates from the rivers Lek and Noord, at the confluence of which the village is located. To drain the polder, a system of 19 windmills was built between 1738 and 1740. Their purpose was to pump the excess water into a reservoir until the level of the river had fallen enough to pump the water back into river Lek. This group of mills represents the largest concentration of old windmills in the Netherlands, and is today a popular tourist site. They have been a UNESCO World Heritage Site since 1997. windmills-of-kinderdijk-1 Photo credit In Alblasserwaard, problems with water became more and more apparent in the 13th century. Initially, large canals, called "weteringen", were dug to get rid of the excess water in the polders. However, the drained soil started setting, while the level of the river rose due to the river's sand deposits. After a few centuries, an additional way to keep the polders dry was required. It was then the decision to build a series of windmills was taken. At one time there were more than 150 windmills in the Alblasserwaard and Vijfheerenlanden area. This dropped to 78 in the 1870s, but today the total is only 28, of which 19 are in the Kinderdijk area. Although the windmills have been replaced by more efficient diesel pumps, they are still maintained in operating condition because they function as fall-back mills in case of failure of the modern equipment. The windmills were used for the last time during the second World War, when the mechanical pumps could not be used any more due to fuel shortages. During the summer months, the mills are put back in operation again for the sake of the tourists. In one of the windmills a small museum is established with an exhibition about how miller-families lived. windmills-of-kinderdijk-4 Photo credit windmills-of-kinderdijk-2 Photo credit windmills-of-kinderdijk-3 Photo credit windmills-of-kinderdijk-5 Photo credit windmills-of-kinderdijk-6 Photo credit Sources: Wikipedia / UNESCO / World Heritage Site https://www.kinderdijk.com/mills/nederwaard ======================= https://www.kinderdijk.com/ Most of the Kinderdijk windmills are grondzeilers or ‘ground sail windmills’, but there is a difference between the windmills in the Nederwaard water management district (such as the Museum Windmill) and the Overwaard water management district. The eight round stone grondzeilers in the Nederwaard are upper winders, some of which have the winch on the end of a tail pole. They have thatched bodies and an internal water wheel. The sails of a grondzeiler almost touch the ground when it turns, which is where it gets its name. The wind shaft can be turned into the wind by turning the whole upper section, which is known as ‘winding’, which is why these windmills are known as upper winders. Convenient when the wind suddenly changes direction! So what are the differences between the Nederwaard and Overwaard windmills? The Nederwaard commissioned the construction of eight round stone grondzeiler windmills, which were completed in 1738. In that time, as we can see from old paintings depicting the windmills, the Nederwaard windmills were covered in slate shingles rather than a thatched body. The fifth windmill was known as the ‘crooked mill’. It was 65 centimeters out of alignment. It was straightened in 2011 and then restored to working order. The restoration cost over 1 million euros. The bakehouse that belonged to the fifth windmill was torn down and reconstructed by the Museum Windmill, the second Nederwaard windmill. The Nederwaard windmills are not lined up neatly; instead, they are staggered to ensure that they would not block each other’s wind, especially in the event of a prevailing west wind. This was less of a consideration for the Overwaard windmills, since they are spaced farther apart. It would also have been much more difficult to stagger the windmills in the Overwaard polder, since the edges of the Overwaard do not have broad strips of land along the dikes to prevent dike subsidence.