Preferred Strategy for the Southwest Delta

The current integrated preferred strategy is inadequate for the Southwest Delta. The tipping points have already been reached for the protection of the ecology and water quality in this region. As a result, the balance between ‘climate resilience and safety’, ‘economic vitality’ and ‘ecological resilience’ has been disrupted at the cost of ‘ecological resilience’. 

The strategy will focus more on the national and regional implementation of spatial adaptation. This will improve resilience to weather extremes resulting from climate change impacts such as floods and drought. The strategy ensures that the agendas and measures for flood risk management, fresh water and spatial adaptation are adequately aligned and that they fit in with the desired spatial planning of the Southwest Delta. 

Area approach 

The new preferred strategy establishes, on the basis of the 2015 Area Agenda, more connections with functions such as shipping, nature, fishing and leisure activities. There are also closer links between the water system and the land areas. Examples are innovative area concepts such as flood-defence landscapes and dynamic dike zones. 

With the integrated preferred strategy and the 2050 Implementation Programme for the Southwest Delta, the partners in the Southwest Delta Area Consultation Platform are working on a single storyline and an integrated approach for the entire area, with a focus on links with local and area initiatives. The 2050 Implementation Programme, which has still to be drafted, zooms in on eight water and land areas with the associated area processes. This is done on the basis of regional and national policies for the sustainable and climate-resilient use of space. The guiding principles are spatial design power and general prosperity. 

Long term 

The current strategy through to 2050 serves as a starting point for the long-term perspectives. The Southwest Delta exploratory system analysis looked at possible solutions for system modifications in the main water system in the four long-term conceptual perspectives of the Delta Programme: seaward, protect open and closed, and accommodate.

The development of adaptation pathways for the long term helps visualise current and long-term dependencies. Long-term strategy development in the Western Scheldt area and the Ghent-Terneuzen Canal will be the subject of international discussions with Flanders. 

Water quality and nature

The major national and international ecological assets in the Southwest Delta are under pressure because of deteriorating water and nature quality due to human interventions. The measures in the Natura 2000 management plans and the Water Management Plans are leading to improvements but they are still inadequate for the attainment of the Natura 2000 and WFD objectives.  

To break with this trend, additional stimulus is needed from national programmes such as Spatial Arrangements and the Programmatic Approach for Large Waters (PAGW). An example of an implementation measure is the regular raising of tidal flats in the Eastern Scheldt so that they remain available for birds that forage there.  

The PAGW ecological target scenario was established in 2050 for the Rhine, Meuse and Scheldt estuaries. The target scenario is a non-optional building block. It provides direction and support for the development of the large waters on the road to a healthy and resilient ecosystem by 2050, looking ahead to 2100. It also sets out the systemic measures that contribute to achieving the scenario goals.  

Flood risk management

The preferred strategy sets out how we can keep the existing flood defences up to par until 2050 in accordance with the current insights and standards. In the context of the implementation of the Flood Protection Programme, preparations are being made for a range of dike upgrades. The water authorities and Rijkswaterstaat completed the assessment of all dike sections in 2022. The result: 25% of the dike sections will require upgrading before 2050 in the context of the Flood Protection Programme. This is a major and complex challenge, not least because of space limitations and the requirements of nature legislation. Limited capacity and funding also represent major challenges for water authorities. To continue working as effectively as possible, opportunities are being sought for a joint, integrated approach for each area. For example, every dike upgrade operation includes an assessment of the possibility of innovative dikes: dikes that open up opportunities in the short term for areas such as nature, leisure activities, cultural heritage or housing. Finally, consideration is being given to an transitional polder concept in the Western Scheldt and preparations are being made for a Welzinge and Schorerpolder pilot project for climate-resilient flood risk management, robust Scheldt nature and sustainable agriculture. 

Separate strategies have been defined for  

• the Grevelingen and Volkerak-Zoommeer lakes. This strategy focuses on establishing connections between flood risk management and freshwater supplies in conjunction with ecology and the economy. 
• the Eastern Scheldt. The strategy with an open, movable barrier for the Eastern Scheldt focuses on the future-resilient optimisation of the closure regime for the storm surge barrier, dike upgrades (and the associated innovations), and sandbank and riverbank replenishment. A sediment strategy has therefore been developed to maintain the sandbanks as a foraging habitat for birds. 
• the Veerse Meer lake. This strategy focuses on optimising water level management and improving water quality. 
• the Western Scheldt. This strategy focuses on dike upgrades (and the associated innovations) in combination with sound sediment management and the optimisation of the dredging and deposition strategy. 
• The Coast and Voordelta. The protection strategy, which is about making the coast and the Voordelta rise in line with the sea level, is linked to the spatial ambitions where possible. 

Fresh water

The Southwest Delta has two large freshwater basins that are supplied by the rivers: the Biesbosch/Hollandsch-Diep/Haringvliet and the Volkerak-Zoommeer lake. The freshwater strategy focuses on maintaining and, where possible, optimising these freshwater supplies for the surrounding areas. The Southwest Delta also includes areas surrounded by saline water where the influx of fresh water from the outside is not possible. In these areas, the strategy targets the improved retention of rainwater in the soil and the optimisation of water use by the business sector.  

The second periodical evaluation has worked towards a package of measures with regional contributions. That included the Zeeland Freshwater Living Lab, a programme which experiments with measures to establish a better equilibrium between freshwater supplies and demand in areas of Zeeland where water influx is not possible. 

Because of the link with the freshwater supplies in the Southwest Netherlands, the drinking water company Evides has joined the Area Consultation Platform for the Southwest Delta. National and regional governments are also collaborating intensively in the Area Consultation Platform to identify the consequences for freshwater availability and to develop appropriate solutions. There is administrative coordination at the area level for this purpose between the three provinces involved: Noord-Brabant, Zeeland and Zuid-Holland. 

Spatial adaptation

The Southwest Delta includes three working regions that focus on spatial adaptation: Zeeland, Goeree-Overflakkee and the Southern Netherlands. Each region is developing its own approach. In Zeeland, the provincial parties have drawn up an action plan for the ‘Zeeland Climate Adaptation Strategy’ and they have signed a six-year implementation covenant. The strategy focuses on a robust freshwater situation and multi-layer flood risk management: a combination of flood prevention, spatial planning measures to mitigate consequences, and crisis management.   
The provinces of Noord-Brabant and Limburg are working together on a Climate Adaptation Implementation Programme for the Southern Netherlands. Two of the thirteen working regions are located in West Brabant and they are part of the Southwest Delta. The provincial authority of Noord-Brabant surveyed the climate risks, provided municipal authorities with support in the area of risk dialogues, and developed the Climate Portal for sharing knowledge. 

In 2025, the government authorities will implement supra-regional stress tests and risk analyses for problems with excessive water. The results, and the strategies and measures to be developed, will be included in the preferred strategy for the Southwest Delta. The intention is to develop a cyclical implementation programme for this purpose. Problems with excessive water, spongy soils and drought are themes that will be given a place in the amended preferred strategy. 

Climate adaptation also requires space. Spatial planning therefore still needs to be given a much more prominent role in the preferred strategy. The question here is: how can the preferred strategy be developed so that all the spatial transitions can be implemented in climate-adaptive ways?