The Haringvlietdam bridges 4.5 kilometers of water between Goerree-Overflakkee and Voorne-Putte. The dam was completed in 1971. Apart from the Oosterscheldekering , the construction of the Haringvlietdam took the most time: 14 years. The Haringvlietdam had two functions: firstly, the dam was to protect against a future flood disaster and secondly, the dam was to discharge Rhine and Maas water to the North Sea . A closed dam would therefore not suffice. The dam has seventeen openings that regulate the amount of water that flows through the new Waterway to the North Sea . If the water levels in the vicinity of Rotterdamrisk of getting too high, the sluices can discharge extra river water into the sea. In addition to the sluices, a lock for shipping was also built. The cable car method was used to seal the rest of the hole. To spare nature special tunnels were made in a number of pillars; fish can use it to swim from the Haringvliet to the North Sea (and vice versa), even when all locks are closed.
The Haringvliet locks and the Haringvlietdam lie between the North Sea and the Haringvliet and regulate the water level in a way that is comparable to opening or closing a tap. That is why the lock is also called the Crane of Europe.