Barrier dyke

Principle and advantages of barrier dikes:
The energy of the storm waves is not successively dissipated by the slightly rising height of the earth-sand dykes, as is usually the case, but is reflected by a vertical barrier.

Principle and Advantages of Barrier Dikes

This results in:

  1. High mechanical stability of the barrier, depending on its thickness, construction, and anchorage in the ground, which often consists of sand and silt. The pressure of a strong tsunami impulse wave has been calculated at 7 tons per m² [1].
    Position and stability are reinforced on the landward side by a steep embankment.
  2. Erosion and corrosion are largely prevented through the choice of materials and by using a movable parapet. Repairs of the barrier dikes are not expected for at least 100 years.
  3. Depending on sand transport on the sea side, the vertical character of the barrier dikes can be maintained by occasional dredging.
  4. The compact construction allows for short construction times. The Wadden Sea is protected.
  5. The later height increase of the barrier dikes, required due to global warming, is simple and efficient.
  6. The permeability to seawater is negligible, so salt contamination in the marshes can be reduced.
  7. Consumption of sand and clay is low compared to conventional dikes. The structure can also serve as a repository for construction and nuclear concrete waste.
  8. The construction costs of barrier dikes are in the same range as those of conventional dikes (4 to max. 9 million euros per km).
  9. Land gain is enormous: for 1,100 km of North Sea coastline, this corresponds to 11,000 hectares or 1.4 billion euros, i.e. 1.3 million euros per km of barrier dike.
    In addition, the Halligen islands can be saved and new land can be reclaimed.

Additional advantages of the barrier dikes include:

  1. Tourism: Bicycles and electric buses on the top concrete road.
  2. Use of the stable structures for wind turbines and their maintenance via the concrete road.
  3. Use of the stable structures for communication transmission towers.

[1] H. Elsafti, H. Oumeraci and H. J. Scheel:
Hydrodynamic Efficiency and Loading of a Tsunami-Flooding Barrier (TFB),
Coastal Engineering 2016, pp. 1–12.
General Protection Engineering GmbH, 05/2019.

Preliminary Cost Estimate

For 1,100 km of North Sea coastline with 2,200 wind turbines at 7.5 kW each and 1 million euros per unit: 2.2 billion euros
Barrier dikes 1,100 km × 5 million euros: 5.5 billion euros
Total: 7.7 billion euros
2,200 × 7.5 kW = 16.5 GW
After deducting land gain (1.4 billion euros), the total is 6.3 billion euros.