Afsluitdijk, (IJsselmeer Barrier Dam)
The Afsluitdijk is a major causeway in the Netherlands, constructed between 1927 and 1932 and running from Den Oever on Wieringen in North Holland province, to the village of Zurich in Friesland province, over a length of 32 kilometres (20 mi) and a width of 90 m, at an initial height of 7.25 m above sea-level. It is a fundamental part of the larger Zuiderzee Works, damming off the Zuiderzee, a salt water inlet of the North Sea, and turning it into the fresh water lake of the IJsselmeer. The Afsluitdijk was the initial demonstration site for a 130 km/h speed limit in the Netherlands.
Beside the dike itself there was also the necessary construction of two complexes of shipping locks and discharge sluices at both ends of the dike. The complex at Den Oever includes the Stevin lock (named after Hendrik Stevin, a son of mathematician and engineer Simon Stevin) and three series of five sluices for discharging the IJsselmeer into the Wadden Sea; the other complex at Kornwerderzand is composed of the Lorentz locks (named after Hendrik Lorentz, the famous physicist, who personally did the calculations of the tides that were crucial to the construction of the Afsluitdijk) and two series of five sluices, making a total of 25 discharge sluices. It is necessary to routinely discharge water from the lake since it is continually fed by rivers and streams (most notably the IJssel river that gives its name to the lake) and polders draining their water into the IJsselmeer.