Dike reinforcement Den Oever-Den Helder

The Wieringer Zeewering, Amsteldiepdijk and Balgzanddijk protect over 1.2 million North Hollanders from high water. In some places they no longer meet the latest safety requirements. That is why the high water board is working on strengthening the dikes. The design is now ready and a draft project decision with an environmental impact report (MER) has been drawn up. This describes the approach to the reinforcement and the consequences for the surrounding area.

Invitation to consultation hours

From October 24, 2025 to December 4, 2025, the draft project decision, environmental impact report (EIR) and draft environmental permits for the Den Oever - Den Helder dike reinforcement will be available for inspection.  

To answer questions about the plans and permits, we are organizing two consultation hours.  

Walk-in at the Village Hall Westerland

Date: Tuesday, November 4,
Time: 4:00 - 7:00 p.m.
Location: Westerland Village Hall, Westerlanderweg 61, 1778 KM Westerland 

Digital consultation

Date: Wednesday, November 19,
Time: 7:00 - 9:00 p.m.
Location: Online via Microsoft Teams: 

Participate in digital consultation 

What is on display? 

During the inspection period, you can comment on: 

  • The draft project decision for the dike reinforcement;
  • environmental impact assessment (EIA);
  • the draft environmental permits:
    • Environment plan activity performing works (Municipality of Hollands Kroon is competent authority;
    • Building environmental plan activity (municipality of Hollands Kroon is competent authority);
    • Water activity (Rijkswaterstaat is competent authority);
    • Natura 2000 activity (Province of North Holland, outsourced to Omgevingsdienst Noord-Holland Noord is competent authority);
    • Flora and fauna activity (Province of North Holland, outsourced to the North Holland North Environmental Service.  

Where can you find the pieces? 

The documents will be available digitally from Oct. 24 via:  

You can also physically view the documents:

  • at Hoogheemraadschap Hollands Noorderkwartier, Stationsplein 136, Heerhugowaard (by appointment only by calling 072 - 582 8282 or by e-mail to dijkversterkingdodh@hhnk.nl, quoting case number 1092901);
  • at Provincie Noord-Holland, Houtplein 33, Haarlem (by appointment only by calling 023 - 514 4440 or by e-mail to info.div@noord-holland.nl, quoting case number 1092901). 

How can you respond? 

You can submit a view in three ways: 

  • Digital - send an e-mail to post@noord-holland.nl   
  • By mail to:
    Gedeputeerde Staten van Noord-Holland
    Postbus 3007
    2001 DA Haarlem
  • Oral - by phone or at the county office (after making an appointment to do so by calling 023 - 514 44 40 or emailing info.div@noord-holland.nl) 

Please include the following information in your view: 

  • the subject: 'Coordinated procedure/draft project decision Dike reinforcement Den Oever - Den Helder';
  • case number: 1092901;
  • Which draft decision your view is about;
  • the date you respond;
  • Your name and address information;
  • What you think of the draft permits. For example, whether, in your opinion, they contain inaccuracies or overlook issues and/or interests. You can also indicate how these decisions affect your own interests and why. Of course, you can also raise other relevant issues. 

For information on the content or procedure, please contact Province of North Holland. Call 023-514 44 40 or email info.div@noord-holland.nl quoting case number 1092901. 

What happens next? 

Everyone who submits a view will receive confirmation and later also notification of the response to it and the final decisions. Then there is the possibility to appeal to the Council of State. 

Interested parties may also lodge an appeal without having first submitted an Opinion, although it is advisable to do so. For non-interested parties, they can only appeal if they have submitted an opinion, or if they had a good reason for not doing so. Note that you can only appeal rules that protect your interest. 

Looking ahead to implementation 

In the meantime, we will start preparing for the dike reinforcement. This will ensure that we can start work outside as soon as possible. The work is expected to start in 2028 and be completed in about three years. 

Water safety tasks

Failure mechanismDescription of failure mechanism

Balgzand dyke

Amsteldiepdijk

Wieringer Seawall 

Inward stability (STBI).The dike is not stable enough to resist high water. As a result, parts of the dike may shear on the land side, causing the dike to collapse. 

3.65 km

Asphalt lining water overprinting (ASP).During high water, the water table inside the dike rises. When the water level outside the dike body drops rapidly, the water level inside the dike can cause a large pressure from the inside of the dike against the underside of the revetment. If the asphalt revetment cannot provide sufficient counter pressure, the dike collapses. 

1.60 km

2.24 km

Zetsteen lining (ZST).Waves and currents can damage the different layers of bedrock. When the carpet pad erodes, the dike can collapse.

3.25 km

Grass cladding (GEBU).The grass revetment on the outer embankment may erode due to load from wave impacts or wave run-up.

0.5 km

Asphalt cladding corrugations (AKG).Repeated wave impacts on the asphalt revetment can cause cracks in the asphalt and cause the dike to fail. 

1

,6 km

Dike strengthening measures explained by dike

Balgzand dyke

Inside

To improve the stability of the dike, a longitudinal construction is being placed on the inner side (Balgzand Canal side) over a length of 3.65km. This wall goes 12 to 30 meters deep into the ground and contains regular openings to allow groundwater to flow properly.

Exterior 

The lower edge of the existing asphalt overlay will be replaced with set stone. This new covering will be 1.5 to 2.5 meters higher. Under the settstone will be layers of crushed stone, geotextile and a thick clay layer, which together provide better protection against wave action and water pressure.

Amsteldiepdijk

On the Amsteldiepdijk and a section of the Balgzanddijk, the outer dike revetment will be reinforced over a length of 2.24 kilometers. As with the Balgzand dike, the lower edge of the asphalt will be removed and replaced with bedrock.

Wieringer Seawall

On the Wieringer Seawall, the dike reinforcement design consists of replacing the outer dike revetment in three forms: replacing zetestone revetment (section 3), applying open stone asphalt (section 4), replacing asphalt revetment (section 5).

Over a length of 3.25 km, the current bedrock will be replaced with new bedrock. The current settlement consists of basalton columns with a column height of 35 cm. The basalton pillars will be replaced by the same height (Basalton STS+). An ecotop layer of lava rock will be applied to the new headstone. This creates a rough surface that provides better adhesion opportunities for flora and fauna. The appearance of the dike will remain the same as it is today. 

In four sections totaling about 500 meters, the current grass revetment will be replaced with open stone asphalt (OSA). This revetment will be laid concealed: the sod and upper soil layer will be removed. Below this will be a layer of geotextile containing the open stone asphalt (OSA), and on top of the OSA will be a living layer 30 cm thick, in which grass and herbs can grow.

The new grass layer will be sown with an herb-rich mixture appropriate to the management of dikes by HHNK. After the work, the dike will continue to look green and natural, similar to the current situation.

In two sections totaling 1.6 kilometers, the existing asphalt lining of the dike will be partially replaced. The top layer (wearing course) will be removed and replaced with a new layer of hydraulic asphalt concrete (WAB), which will be applied to the existing foundation. At the transitions from asphalt to grass on the crest of the dike, grass concrete tiles will be placed. These tiles have openings through which grass can grow. This provides extra strength and a natural transition to the grass revetment.

Contact

Do you live near the Den Oever-Den Helder dike reinforcement project or are you otherwise involved in this area? This news page will keep you informed of current developments surrounding the dike reinforcement.

For more information about this project, contact environmental manager Britte Mussche at 072 - 582 8282, dijkversterkingdodh@hhnk.nl or through the contact form.

Opinions, reports and notes

Notification participation

In this dike reinforcement project in the Noordkop, we are working according to the guidelines of the Omgevingswet. Therefore, at the start of the planning phase (early May 2021) we published the participation notification. In it we indicated how and when we would inform the surrounding area and ask them to participate, with the ultimate goal of arriving together at an established Project Decision. 

Preferred Alternative

The Executive Board adopted the preferred alternative (VKA) for strengthening this dike section on June 23, 2020. The most suitable solution per dike section (Wieringer Zeewering, Balgzanddijk, Amsteldiepdijk) is now known and can now be worked out in more detail.

Survey map with locations of dike reinforcement Den Oever - Den Helder

What's going on?

On the outer side of all three dike sections, the revetment, consisting of zetestone, asphalt and grass, does not comply in large parts. And along the Balgzand Canal, the dike is not stable enough on the inside in certain sections.

What does the VKA look like?

During the reconnaissance phase, we looked at a wide range of possible solutions for all three levees together with the environment. The VKA consists of:

  1. On different parts of the three dike sections we are reinforcing the revetment on the outside. It concerns asphalt, grass and stony revetment.
  2. Of the Balgzand dike, we are reinforcing the inner toe of the dike by a paving in certain sections.

Between 2017 and 2019, we organized several dike evenings (meetings) for stakeholders, local residents and other interested parties. During these meetings, among other things, we showed possible solutions for the dike reinforcement. We also provided feedback on questions and wishes we collected from the surrounding area. In the fall of 2019, we presented the preliminary choice for the preferred alternative. The Executive Board adopted the preferred alternative on June 23, 2020. The preferred alternative was designed together with the environment.

Working on a project decision

At the end of the plan development phase, the board lays down the design for the dike reinforcement in a project decision. This decision must be approved by the Provincial Executive of the province of North Holland.

Why a notification?

The next project phase, the plan execution phase, started in 2021 and ends with a project plan/project decision. This phase involves working with the surrounding area to develop and design the preferred alternative (VKA). This phase determines what the dike will look like after the reinforcement. This phase will also include determining which co-option opportunities can be implemented. The purpose of the announcement is to inform you about the participation during the planning phase. View the full announcement.

More information about the dyke sections

Wieringer Seawall

The Wieringer Zeewering is the section of dike that runs from Den Oever to the Amstelmeer and is over 10 kilometers long. The dike is loaded directly from the Wadden Sea. The hinterland is the former island of Wieringen and is mainly rural in nature. The foreland is the Wadden Sea, an area of high natural value. Along the dike are places like Den Oever and Hippolytushoef.

Amsteldiepdijk and Balgzanddijk

The Amsteldiepdijk connects to the Wieringer Zeewering and runs to the Van Ewijcksluis. The Balgzand dyke is an extension of this and continues up to the sluice at Oostoever.

The dikes are enclosed by water on both sides; on the outside is the Wadden Sea. The Amsteldiepdijk was constructed in 1924 as a pilot for the Afsluitdijk, creating the Amstelmeer on the inside. On the inside of the Balgzand dike is the Balgzand Canal, an important drainage canal for the Water Board. In some places there is a foreland barrier, a dike in front of the dike into the sea. Together, the Amsteldiepdijk and the Balgzanddijk are about 10 kilometers long.

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