Low probabilities -
large consequences

Reducing the vulnerability of the Dutch population to floods

In the winter of 1953, a storm tide breached the dykes in more than 90 places in the south-west of the Netherlands. The devastating flood that followed claimed over 1800 lives and caused more than 700 million euros worth of damage. This catastrophe initiated the Delta works and an extensive reinforcement of existing dykes and levees, currently making the Netherlands the best protected delta in the world.

However flooding can never be ruled out completely. Around 59% of the Dutch land surface is prone to flooding including 26% that lies below sea level. In terms of consequences, floods are among the worst disasters that can hit the Netherlands.

Flood-prone areas in the Netherlands

Flood-prone areas in the Netherlands Around 59% of the Dutch land surface is prone to flooding including 26% that lies below sea level. Below sea level 26% Above sea level 33% pbl.nl
Flood-prone areas in the Netherlands Around 59% of the Dutch land surface is prone to flooding including 26% that lies below sea level. Below sea level 26% Above sea level 33% pb l . n l

Loss of lives will cause devastation

Although the probability of flooding may have been reduced considerably, it still remains. And the potential consequences would be huge. Since 1953, the Dutch economy has grown and its population has increased - almost 70% of which live in flood-prone areas.

Population in areas at risk of flooding in the Netherlands is growing

Population in areas at risk of flooding in the Netherlands is growing million inhabitants pbl.nl Low projection High projection 10 15 5 0 1953 1972 2012 2030 2050
Population in areas at risk of flooding in the Netherlands is growing 10 15 5 0 million inhabitants pbl.nl High projection Low projection 1953 1972 2012 2030 2050

The scale of disruption and devastation, therefore, would be much larger than 60 years ago. Floods in the densely populated Dutch delta may cause many thousands of casualties and hundreds of thousands more would be affected in some way. The breakdown in transport, energy and communication infrastructural networks would further increase the disruptive impact. And risks will only increase, due to climate change and the continual growth in the economy and population.

How could this be avoided?

To cope with these future risks, Dutch government has developed a new flood risk management policy which focuses on two goals:

  1. to further reinforce the numerous stretches of dykes and levees (protection)
  2. to reduce the potential consequences of flooding. This could be done not only through sustainable spatial planning and revised contingency plans, but also by reinforcing dykes and levees.

The combination of protection and management is known as the multilayered safety concept.

Multilayered safety concept: protection and management

Multilayered safety concept: protection and management Contingency plans Organisation of disaster and crisis management Sustainable spatial adaptation Spatial organisation to reduce the consequences of flooding Protection Flood prevention, the backbone of the flood risk management policy
Multilayered safety concept: protection and management 3. Contingency plans Organisation of disaster and crisis management 2. Sustainable spatial adaptation Spatial organisation to reduce the consequences of flooding 1. Protection Flood prevention, the backbone of the flood risk management policy