Krammer locks

Krammer locks (1978-1983)

An important part of the Philipsdam is the Krammer lock complex that continues to allow ships to pass between the Scheldt and the Rhine. To prevent salt water from the Oosterschelde from ending up in the fresh water Volkerak lake- or vice versa – a salt-fresh separation system has been built into the Volkerak locks. Hereby, the fact that salt water has a higher density than fresh water is put to good use. When salt and fresh water are mixed, the salt water goes down. When a ship enters the lock from the Oosterschelde, the lock gates are closed behind the ship first. Then the salt water is pumped away from the bottom of the lock and fresh water is let in at the top of the lock. When the water level has dropped sufficiently and the salt water is pumped out, the lock door opens. There is always some salt water entering the Volkerak and fresh water getting into the Oosterschelde, but that amounts to so little that it has no influence on the marine environment.


Commercial and recreational

The largest two Krammer locks are 280 meters long and 24 meters wide and are therefore large enough to accommodate inland ships with four barges. In front of the locks, 1.3 km long outer harbours have been constructed for ships to moor. To the north of the two locks for commercial shipping, a lock for recreational boats was built, with a 75 meter long outer harbour. In 1994 a second lock was built for pleasure crafts.