Water Safety Delta Decision

The Delta Decision on Water Safety is focused on the new water safety standards. These standards were set using a risk-based approach that takes into account both the risk of flooding and the possible ensuing consequences. The scale and scope of the consequences determines the level of the standard.

Water Safety Delta Decision

With the new standards, a basic safety level of 10-5 applies to everyone living behind the dikes and dunes. This basic safety level means that the risk of fatalities due to flooding is no higher than 1 in 100,000 per year. A higher level of protection may apply for areas in which flooding could lead to large groups of casualties or significant losses. A higher protection level may also apply if so-called “vital functions” are present. This is the case for the major gas production area in Groningen for which a higher level is proposed: the entire country would suffer if the supply were disrupted. Flood defences that already offer the required protection level will be properly maintained. If the standard of the flood defences needs to be raised, dike strengthening or river widening will take place. In the preferred strategies, the sub-programmes have indicated the measures that are necessary for both the short and long term. The preferred strategies constitute the basis for the Water Safety Delta Plan implementation programme.

The sub-programmes also investigate whether, in addition to dikes, dams and dunes, other types of measures could also make a contribution (multi-layered safety):

  • Layer 1: measures to prevent flooding (like dikes, dams and dunes)
  • Layer 2: counteracting the consequences of flooding through spatial planning
  • Layer 3: counteracting the consequences of flooding through emergency management