The prepared floodings was a very important part of the Copenhagen fortifications, specially on the northern front
The water for these major floods was taken from the Furesøen (lake) up north.
This lake was 20 meters above sea level.
The northern flooding was led east to the Öresund through Lyngby by prepared canals.
At the Öresund it was neccesary to have 7 pools and 8 dams as there was a large terrain difference towards the Öreound.
the southern flooding was supplied from the northern .
The main target was to flood The Kagsmosen (an existing bog area) to 12 meters above sea level.
The filling time for both the prepared floodings was calculated to 8 days when 22 m3 per second was added.
The water level in the Furesøen (lake) would drop 1½ meters if both floodings were activated .