IJsselmeer region

The IJsselmeer region plays a pivotal role in Dutch water management. The region is of great value in terms of the natural environment and cultural history. The IJsselmeer Closure Dam (Afsluitdijk) has made the entire region safer and has enabled land to be reclaimed. A freshwater reservoir has been created which is of benefit to agriculture, industry, and nature in a large part of the Netherlands. Society uses the lakes and their banks in many different ways, such as recreational activities, the extraction of drinking water, and shipping.

In order to continue to use all these functions to their full potential and to make improvements wherever possible, it is important to respond flexibly to new developments and insights. The Preferential Strategy for the IJsselmeer Region aims to keep flood protection and the freshwater supply up to par, and to expand flexibility. The focus in the years ahead will be on fleshing out the strategy. Pursuant to the IJsselmeer Region Pact and the IJsselmeer Region Agenda for 2050, the region is exploring opportunities regarding an integrated approach to the required measures. The Delta Decisions constitute an important point of departure and framework in this regard.



The sea level is continuing to rise, possibly at a pace faster than was originally assumed. This has already made it more difficult to discharge water from the IJsselmeer into the Wadden Sea. At the same time, expectations are that climate change will necessitate an increase in the volume of river water to be discharged into the IJsselmeer in extreme weather conditions. Conversely, during prolonged drought the supply may decrease. This became manifest during the summer of 2018, when the IJsselmeer salinised as a result of the unexpectedly long period of drought. The level management must be able to respond to these changes, especially as climate change and economic developments are expected to result in an increased demand for fresh water

Flood risk management

In order to secure long-term flood protection,  several primary flood defence systems will be tackled:

  • The work on the IJsselmeer Closure Dam commenced in late 2018. The dyke will be improved along its entire length and both lock complexes will be provided with storm surge barriers. The project is scheduled to be completed by 2022.
  • The Houtrib dyke improvement between Enkhuizen and Lelystad is in progress. A section of this dyke will be improved with rubble and another section with wide, sandy shores. The project will be completed by 2020.
  • The plans for the improvement of the Markermeer dykes were available for public inspection at the end of 2018. Seven appeals have been lodged, which the Council of State is expected to consider by the second half of 2019. Preparatory work has commenced nonetheless.
  • The draft decisions regarding the Marken dyke improvement have also been open to public inspection. The project is expected to be launched in 2022.  

 Freshwater supply

The freshwater supply in the IJsselmeer Region can be maintained by implementing a cohesive set of measures in the main water system (the large lakes), regional water systems (smaller watercourses, drainage water, and canals) and among consumers. The availability of fresh water  will be expanded by introducing flexible water level management in the IJsselmeer, Markermeer, and Zuidelijke Randmeren lakes. In the near future, this will make a 20cm “extra layer of water” available as a structural water reserve. On 14 June 2018, the Minister of Infrastructure and Water Management endorsed the new water level ordinance for the IJsselmeer Region.

In early 2019, Rijkswaterstaat set down the “Operationalisation of Flexible Water Level Management” protocol. This protocol, which has been formulated in collaboration with district water boards and other stakeholders, comprises operational agreements regarding the regulation of the IJsselmeer and Markermeer water levels. The Hoeckelings dam will be adapted to level fluctuations on the basis of the building with nature concept. The Hollands Noorderkwartier district water control board, the province of Noord-Holland, and the Markermeer Dykes Alliance have contributed to the plan. All the measures involved are scheduled to be completed by the end of 2023.

Rather than compensating for the increasing regional demand by allowing an increase in water consumption, the authorities in charge of the regional water systems aim to keep water consumption constant by implementing measures in the region, such as more efficient flushing and introducing adjustable weirs. Farmers and industrial enterprises will also be encouraged to save water, for example through underground freshwater storage and the reuse of process or cooling water. Agreements to this effect have been set down in the Administrative Agreement on freshwater supply measures in the IJsselmeer Region 2016-2021.

A random selection of the projects and studies:

  • The Fryslân and Hunze en Aa’s district water boards are working on brook restoration in order to facilitate surface to groundwater flow;
  • The province of Flevoland is working on the soil structure to improve water retention;
  • The province of Groningen has explored which measures hold promise for prolonged water retention in the soil;
  • In the Drentse Aa catchment area, a study has been conducted into the impact of climate change on the wet nature in the Natura-2000 areas;
  • The Spaarwater programme is exploring ways to store or preserve fresh water under saline conditions;
  • The province of Noord-Holland is conducting studies, in collaboration with farmers, into the water quality, soil moisture, and water levels in parcels, drainpipes, and ditches;
  • The island of Texel is constructing freshwater weirs to retain fresh water.

Spatial Adaptation

In the IJsselmeer Region, several examples of Spatial Adaptation have already been realised.

  • In the city of Den Helder, part of the Nieuw Den Helder neighbourhood is being renovated in a climate-adaptive manner;
  • A project on the island of Texel revolves around the climate-adaptive saline cultivation of potatoes and flower bulbs;
  • In Almere Poort, local wadis have been constructed between roads and houses in order to combat waterlogging;
  • The city of Almere has gained experience with concrete spatial planning measures during a major overhaul of the Regenboogbuurt district.

IJsselmeer Region Pact

The regional parties involved have joined forces in the IJsselmeer Region Administrative Platform to monitor progress, to schedule measures, and ensure an efficient exchange of information. However, the ambitions of the platform extend beyond the Delta Programme. They also involve capitalising on linkage opportunities, synergy, and reinforcing spatial quality in combination with new (economic) developments. On 6 March 2015, government authorities and NGOs in the IJsselmeer Region set these ambitions down in an administrative agreement, the “IJsselmeer Region Pact”.

Potential amendment of Delta Decisions and Preferential Strategies

The Delta Decision on the IJsselmeer Region is resilient. This is the preliminary conclusion of the review that commenced in 2018. For the time being, the Preferential Strategies for flood risk management and the freshwater supply up to 2050 are up to par. Until 2050, water will be discharged into the Wadden Sea through a combination of discharge by gravity (if possible) and pumping (if need be). By 2022, the IJsselmeer Closure Dam project will be supplying the required pumping capacity. The new IJsselmeer water level ordinance constitutes the basis for a structurally available freshwater supply. The results of the Integrated Study into Flood Risk Management and Water Level Management (ISWP) – which focused on the long-term water management of the main water system (beyond 2050) – have been discussed in the IJsselmeer Region Administrative Platform. On 4 April 2019, the Platform decided to examine which recommendations ensuing from the ISWP study can already be accommodated in the ongoing review, and which recommendations can only be considered in the subsequent review or at a later date, because they still involve too many uncertainties or because topics require further research. The impact on the regional system is taken into full consideration in the elaboration of the ISWP recommendations for the main water system.

Integrated Study into Flood Risk Management and Water Level Management of the IJsselmeer Region (ISWP)

The Ministry of Infrastructure and Water Management (Directorate-General for Water and Soil Affairs) has commissioned the Rijkswaterstaat Water, Traffic and Environment department (WVL) to conduct a study  into winter water discharges and winter flood protection beyond 2050. This study does not cover the freshwater supply. During winter, the large excess water volumes in the IJsselmeer Region are drained by gravity into the Wadden Sea. Without additional measures, the IJsselmeer water level will rise along with the sea level, as will subsequently the other lakes. This can only be prevented by constructing high-capacity pumping stations, as they will need to drain the entire IJssel discharge volume in addition to water from the region. The rate at which the required pumping capacity increases depends on the accepted rise in the IJsselmeer water level. However, a rising water level will have a negative impact on the region. Flood defence systems will need additional improvement, moveable barriers need to close more frequently, and nature outside the dykes will drown. In addition, the rising water level will complicate the management of regional waters in the vicinity. In the event of a higher water level, the cost saved by pumping will roughly equal the additional cost for improving the flood defence systems. This means that if the other negative effects are also taken into consideration, there is currently no reason to opt for a rise in water level. However, the ISWP study has recommended to keep open the option of a maximum rise of 30 cm in winter water levels after 2050.

The ISWP study has ensued from the IJsselmeer Region Delta Programme, following the conclusion that a great deal of knowledge was available on flood protection, water drainage, and water level management in the IJsselmeer Region, yet information on the interconnectivity of such issues was lacking. The Deltares research agency, HKV Consultants, and the water authorities have contributed to the study. The IJsselmeer Region Administrative Platform will advise the Minister on how to deal with the ISWP study recommendations. Wherever relevant, the outcomes will be included in the first six-year review of the Delta Decisions in Delta Programme 2021.

Delta Programme 2020

Read about the progress made in the IJsselmeer Region in Delta Programme 2020.