The Oranjesluis is a lock and national monument in 's-Gravenzande, municipality of Westland, in the Dutch province of South Holland. On top of the lock is a lock keeper's house, the Jachthuis. This lock is located in the Oranjepolder, in the Maasdijk, and connects the Oranjekanaal on the one side with the inner dike canals on the other side of the dyke.
The lock was built in 1676 by order of the Delfland Water Board and at the expense of William III of Orange. The sluice was first needed for freshwater intake for the gardens of the Honselaarsdijk estate, owned by William III, but the water soon turned out to be too salty, which affected the plants. When the Amersgat was deepened and the canals were cleaned, the lock was also used for drainage. From 1888 the lock has only been used for water outlets.
The costs for the maintenance of the lock were so high that in 1675 the Dikegraaf and the Delfland Water Boards submitted a petition to the Stadtholder asking to declare that the Schieland Water Board also had to bear part of the costs. According to Delfland, they also had an interest in the drainage. This request was never complied with.
In 2006 the capacity of the lock and canal was increased, so that the capacity is now 17,000 liters of water per second instead of 3,000 in the old situation. This water is discharged to the Nieuwe Waterweg by the Westland pumping station.
The Oranjesluizen are a complex of locks in the IJ. They form the boundary between the Binnen- and Buiten-IJ and contribute to maintaining the water level in the North Sea Canal. They also ensure that not too much saline water from the North Sea Canal enters the IJmeer.
Source: Wikipedia