The windmill area at Kinderdijk in the Netherlands was named a UNESCO World Heritage Site in 1997. The system of dikes, polders, windmills and holding basins ("boezems" in Dutch) at Kinderdijk was used for several centuries to reclaim land and keep flood waters away.
Water management is essential in the Netherlands, because a large percentage of the country is actually below sea level. In the 13th century, the Dutch began building dikes and drainage canals to create more farmland. These reclaimed pieces of land, called "polders," had to be carefully managed because they were susceptible to flooding and to subsidence.
Polder boards were created to manage the land so that one single landowner would not have to protect the farms of others from surging water. These polder boards are still in existence today in the form of water management districts. Kinderdijk lies at the edge of two water management districts, Nederwaard and Overwaard.