Dokkumer Nieuwe Zijlen: impressive sea locks

If there is anywhere along the north-east coast of Friesland where human impact is most visible then it is certainly Dokkumer Nieuwe Zijlen, south-west of Lauwersmeer lake. The impressive locks (old-Dutch: zijlen) from 1729 - designed by the famous hydraulic engineer Willem Loré - are still there. 

The lock in the Dokkumerdiep is part of a two-kilometre long ‘overdyke’. This 'overdyking' made the old sea lock in Dokkum superfluous. And furthermore, 600 hectares of new land were created. The lock consists of three lock chambers. Via the sluices it was possible to transport water from the Friesian waters to the Wadden Sea. Ships could sail to the Wadden Sea via the lock.

Still in operation
The complex - with fourteen pairs of doors - was in commission until the Lauwerszee Sea was closed off in 1969 and Dokkumer Nieuwe Zijlen lost its function as a sea lock. But the old lock still has an important function in water management; in 1969, 150 metres farther the Willem Loré lock was built to transport excess water out of the province of Fryslân.

Revolutionary dike design
Along with the Dokkumer Nieuwe Zijlen the professor and hydraulic engineer from Franeker, Willem Loré (1679 – 1744), also gained fame for his revolutionary dike design. By making the dikes wider and, importantly, giving them a more gradual slope, the force of the waves on the dike was not so much broken but exhausted. This meant that the dikes could be a half metre lower yet they were still stronger. What’s more, posts were no longer needed to protect the outer side of the dikes. This made construction and maintenance quite a bit cheaper.


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