Sluice at Driel

 dam, interesting place

The dams was finished in 1966 at a cost of 40mil gulden, 25mil Euro.
The reason for the dams is so that water can be controlled for use as if not areas would be to dry and ships would not have enough water to float in as the ground behind the dams is just that bit higher.
Each visor shaped gates are lifted by a 2x3pk electric motors and if need be can be operated by hand if there is no power for the doors.
The power to lift them is brought over at 1 in 40,000 so the motors don't have to be large.
The reason the are visor shaped is the force of water on the back is the same over the whole area of the door, just like a dam, this makes it a lot safer plus any water passing under the door does a lot less damage to the river bedding and removes any debris better.
They are normally closed but if Holland is expecting high water from Germany they will be raised and this takes about 2.5 hours.
You may think its a long time but water traveling from Switzerland along the Rijn also takes time to reach Holland so they have enough warning. When they are fully open ships can pass below them.
The difference in water level behind the doors and in front can be as much as 4-5mtrs.
Thats the reason for the lock so ships can be lowered or raised to the level behind or in front of the DAM.
It is possible to get from one side to the other even when the visor doors are open as below the complex is a tunnel.

All 3 dams are due for a refurbishment within a short time.