Five Delta Decisions

The Delta Programme is currently working on five ‘Delta Decisions’ aimed at protecting the country against flooding and providing sufficient freshwater supplies.

Updated edition Delta Programme

The Delta Programme 2017, which was launched on Budget Day in September 2016, presents the progress of the implementation of the work on the final 5 Delta Decisions.

Scope of the Delta Decisions

The Delta Decisions focus on 3 main issues:

  • a new approach to flood risk management and freshwater supply;
  • plans for flood-resilient construction and preventing freshwater supply problems;
  • planning flood protection measures along the River Rhine, the rivers into which it discharges, the River Maas, and the IJsselmeer region.

The Delta Decisions are one of the policy priorities of the Ministry of Infrastructure and Water Management.

Delta Decision on flood risk management

The Delta Decision on flood risk management proposes new agreements to protect the Netherlands from flooding, including new standards on the height of dikes. These standards are based on:

  • estimated probability of flooding and
  • impact severity.

The priority is to reduce flood probability as much as possible. This could be done by making sure that the dikes remain intact, but also by adapting the land in such a way that its inhabitants remain high and dry if flooding occurs. It is also important to consider the impact of a breached dike. In some places, it may result only in waterlogged fields. Elsewhere, a whole town could be flooded. The proposal is to improve safety in areas where the risk of flooding is greatest and where the impact is likely to be most severe.

Delta Decision on freshwater strategy

During long periods without rainfall, freshwater can become scarce in the Netherlands. Although this does not affect the supply of drinking water, drought means water shortages for farming, industry and nature. Shortages are expected to occur more often in the future.

It is not always possible for the government to do anything about the problem. However, freshwater users such as farmers, factories and nature management organisations need to know where they stand in such situations. This Delta Decision proposes to determine what the government's role would be, and advocates making agreements on freshwater supply levels.

This Delta Decision also contains plans for increasing the flow of freshwater to certain parts of the Netherlands. For instance, the western part of the country could obtain more water from the Amsterdam-Rhine Canal and the River Lek. In addition, water consumers must be less wasteful, for instance by adopting new technology or storing water in underground tanks.

Delta Decision on spatial adaptation

The Delta Decision on spatial adaptation includes plans for shaping the landscape, in a way that makes society more climate-resilient. Greater effort should be made at the planning stage to consider the potential impact of flooding and keeping cities cool during hot summers. As the climate changes, this is becoming more and more important.

Delta Decision on the IJsselmeer region

This Delta Decision contains answers to 3 questions:

  • What is the best way to discharge surplus water into the Wadden Sea?

    Up to 2050, the best solution is to install pumps in the discharge sluices in the Afsluitdijk.
  • What water levels should be set for the IJsselmeer, Markermeer and Randmeer lakes?

    A flexible water level would be the best solution. It would enable water managers to respond to changes in the weather, such as very heavy rainfall or severe drought. However, there is a fixed agreement that the water level should not be higher than the current winter level.
  • Is the IJsselmeer area large enough to provide sufficient freshwater for other areas?

    The Delta Decision states that this should be no problem up to 2050, provided a flexible water level is adopted and water consumption becomes less wasteful.

Delta Decision on the Rhine-Maas delta

The Rhine-Maas delta consists of the Lower Rhine, and the Rivers Lek, Waal, Merwede and Maas. The area also includes the cities of Rotterdam, Dordrecht, Sliedrecht, Zwijndrecht, Papendrecht, Hendrik-Ido-Ambacht and Alblasserdam.

The Delta Decision on the Rhine-Maas delta answers 4 questions:

  • Is it necessary to build new dams, sluices or dikes in this area?

    No new constructions are necessary.
  • What will happen on the Nieuwe Waterweg if the storm surge barrier no longer meets requirements in 2070? Would it be safer to dam the Nieuwe Waterweg and build large sluices for shipping?

    According to the proposal, a dam is not necessary. A new storm surge barrier will be built, which can be closed in severe weather.
  • How should water discharge be distributed over the various rivers?

    It is proposed that, for the time being, no changes should be made. The government will consider whether measures of this kind are likely to be needed after 2050. 
  • Would it be worth constructing a discharge facility in the Grevelingen to take up surplus water?

    And how would this affect water quality, recreation and leisure activities, and fisheries?It is proposed not to use discharge water into the Grevelingen since this is not necessary for flood protection.