Forts and Floods: Exploring the Dutch Waterline

The Dutch Waterline (Dutch: Hollandse Waterlinies) is a series of water-based defenses designed to protect Amsterdam and Utrecht from potential invasion. It was a defensive line of canals, rivers, and forts that could be flooded to form a water barrier if invaded. Today, the waterline is part of UNESCO World Heritage Sites.

The goal of the Dutch Waterline was to slow down and obstruct advancing enemy forces while the Dutch military regrouped and organized their defense. By intentionally flooding land and cities if invaded, the Dutch Waterline made it extremely difficult for enemies to advance further into the country.

Stelling van Amsterdam the Netherlands

History and Purpose of the Dutch Waterline

Fort K'ijk part of dutch waterline defense

The Dutch Waterline was a series of water-based defenses constructed between 1815 and 1940 in the Netherlands. It spanned 85 kilometers from the Zuiderzee to the Biesbosch, acting as an inland border to protect the western Netherlands.

The Waterline was conceived by Dutch military engineer Jan Blanken after the Netherlands was annexed by France in 1810. Blanken envisioned using the country’s existing lakes, rivers, streams and low-lying lands to create intentional flooding as a defensive barrier against invasions.

Outside building of Fort K'ijk
Many of the sites are Forts

Construction on the Waterline began under King William I in 1815 after the Netherlands gained independence from France. It was subsequently expanded and strengthened over the next century. This included creating a network of forts, fortified towns, sluices, dams and inundation polders that could be flooded to thwart enemy advances.

The Waterline was first tested during the Belgian Revolution in 1830, when Belgian troops invaded the Netherlands. By flooding the lowlands along the line, the Dutch were able to halt the Belgian advance.

The Waterline saw additional combat during the Franco-Prussian War in 1870, World War I from 1914-1918, and the German invasion of the Netherlands in World War II in 1940. Though the Germans were ultimately able to overpower the Waterline’s defenses using paratroopers and aerial bombardments, the series of intentional floods and fortifications significantly slowed their advance.

The Dutch Waterline

By leveraging the Netherlands’ natural landscape and waterways, the Dutch Waterline provided an innovative system of defenses designed to protect the heart of the country by creating expansive, treacherous floods out of farmlands and towns. The deliberate inundations made it extremely difficult for invading armies to advance by ground or transport supplies and artillery. As such, the Waterline formed a crucial part of the Netherlands’ defensive strategy for over a century.

The Dutch Waterline in the Zaanstreek

Parts of the defensive line ran through the Zaanstreek, where a series of forts were constructed in the mid-to-late 1800s to defend strategic locations. This included river forts, land forts and dams designed to control flooding. Not all attractions listed below are within the Zaanstreek, but are nearby, just in the next country, within biking distance or even even walking distance.

The Dutch Waterline Map

As I personally visit each location, I will include additional details for the location;


  • Fort Zuidwijkermeer
  • Fort aan de Middenweg
  • Woudaapsluis bij Molen de Woudaap
  • Fort bij Spijkerboor
  • Fort aan de Jisperweg
  • Fort aan de Middenweg


Want to plan your own visit to one or more of the local Fort’s, check out this website for an Interactive Map and Additional Information.

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As a proud resident of Zaandam since 2010, I'm excited to share the beauty and charm of this city and surronding area. Join me on a journey to explore its picturesque views, meandering Zaan River, and rich history.
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