Delta Decisions (amended)
How will the Netherlands continue to be protected from flooding and freshwater shortages? The national Delta Programme is charting a course for the future. This course encompasses several components, such as the Delta Decisions. These set out choices regarding the strategies pertaining to flood risk management, freshwater supply, and climate-proof and water-resilient spatial planning in the Netherlands.
In 2015, the national Delta Programme partners submitted proposals for the Delta Decisions. The Decisions are reviewed every six years. Delta Programme 2021 presents the amended Delta Decisions.
What is new?
Delta Decision on Flood Risk Management
Its main objective stands: by 2050, every Dutch resident living behind a primary dyke or dam will have a minimum protection level of 10-5. This means: the probability of fatality due to flooding does not exceed 1:100,000 per annum.
Delta Decision on Freshwater Supply
The Delta Decision on Freshwater Supply is aimed at ensuring that by 2050, the Netherlands will be resilient against freshwater shortages. Experts are currently working out the definition of water shortage and are mapping potential remedies. Several measures have already been identified, such as economising, more efficient water retention, and more efficient water distribution. This amended Delta Decision states that acceptance of (and preparation for) damage is also an option. In addition, spatial planning must take more account of freshwater availability.
At the Elevated Sandy Soils, impetus will be given to the transition to active groundwater management. The water availability and spatial adaptation taskings will be addressed in an interconnected manner.
Delta Decision on Spatial Adaptation
Being climate-proof and water-resilient by 2050 remains the point of departure, but the Delta Decision on Spatial Adaptation will have a number of specific interim targets. These will enable more control to be exercised over the implementation of measures. Environmental visions will be paying more attention to the topic of spatial adaptation. In addition, vital and vulnerable functions will be enhanced. By 2050, they must not only be flood-proof, but also capable of coping with waterlogging, heat, and drought.
Delta Decisions on the Rhine-Meuse Delta and Delta Decision on the IJsselmeer Region
- After 2050, the average winter water level of Lake IJsselmeer will be allowed to keep pace, to a limited extent, with the sea level. New in this Delta Decision is that this provision will now also cover Lake Markermeer.
- A comprehensive study into the replacement of the Maeslant storm surge barrier will be conducted. This study will explore both closable open variants and closed variants.
- The rivers Rhine and Meuse are covered by the Integrated River Management programme (IRM). A reviewed strategy for the rivers will be drafted in 2021. The strategy will be finalised and endorsed a year later.
- In the Southwest Delta, more room will be created for the recovery of estuarine nature, i.e., nature developing at locations where saline water and fresh water meet.
- The intertidal area near the Oosterschelde storm surge barrier remains dry during low tide and is flooded during high tide. Shoal and shore-face nourishments are required to combat erosion. Dyke improvements also prevent erosion. These interventions are scheduled within the context of future-proofing the Oosterschelde barrier management.
Decision on Sand
Sand replenishments keep coastal security up to par. The point of departure in these projects remains: “flexible where possible, solid where needed”. As yet, the current volume of 12 million m3 per annum is found to be sufficient. Following the second review, the scope may be adjusted.
- The Preferential Strategy for the Coast sets out a standard approach for the linkage of flood risk management and spatial ambitions. This approach covers the entire coast.
- The Preferential Strategy for the Wadden Region focuses on intensive research into the impact of sea level rise on the Wadden Sea sand system.