Construction of the inundation works

The Defence Line of Amsterdam derived its strength mainly from water. The entire foreland could be flooded in two days by means of an extensive and ingenious system of dykes, dams, culverts, sluices and pumping-stations. Construction of inundation works commenced in 1883. Inundation had to meet certain requirements in order to be effective from a military standpoint. For instance, the water preferably had to be 50 centimetres deep. This was just deep enough to conceal roads, ditches and channels, making it dangerous for enemy troops to enter the area, and furthermore, this relatively low water level made it impossible for the invader to use boats. A sophisticated sluice system was built into the Defence Line to regulate the flooding to within a fraction of a centimetre. The widest inundations were along the north and south sides and the narrowest to the west because of the dunes.

Inundated land at the Defence Line of Amsterdam