A Part of the defence plan, some major floodings north and west of Copenhagen were prepared.
From the Furesö Lake, water was led through the fortress-channel to the Northern and Southern Floodings. Furthermore it was planned to enlarge a marsh area (the Kagsmosen)
All this should be effected with a complex system of dams and channels.that should connect and use the water from existing lakes and streams
To explain the size and complexity of the flooding, 22,5 million cubic feet of water would be led to the southern flooding and 10,5 million cubic metres to the northern.
The flooding, both norts and south, could be completed in 8 days.