Dutch Waterlines

On March 30, 2026, PostNL will issue the Hollandse Waterlinies stamp sheet, featuring photos and maps of 19th- and early 20th-century defensive works in the Netherlands. The Hollandse Waterlinies is the collective name for the Nieuwe Hollandse Waterlinie and the Stelling van Amsterdam. By flooding land during wartime, these defensive lines were able to protect the west of the Netherlands against the enemy.

Dutch Waterlines and design

The New Dutch Water Line and the Amsterdam Defence Line together form the Dutch Water Lines. This UNESCO World Heritage Site is a 200-kilometer-long defensive line comprising 96 forts, 6 fortresses, and 2 castles. In wartime situations, the west of the Netherlands could be protected against the enemy by flooding wide strips of land to knee height. This rendered the land impassable for soldiers, vehicles, or horses, while the water remained too shallow for boats. Construction of the New Dutch Water Line began in 1815 as an improvement and expansion of the 17th-century Old Dutch Water Line. A new construction phase followed in 1880 with the creation of the Amsterdam Defence Line. Should the enemy break through the New Dutch Water Line, the Amsterdam Defence Line would serve as the last refuge for the military staff, the government, and the royal family. In addition to the system of sluices, dikes, and canals to flood land, forts were built at passages and other strategic locations.

The New Dutch Water Line and the Amsterdam Defence Line are among the largest military World Heritage Sites in the world, along with the Roman Limes and the Great Wall of China. The New Dutch Water Line was flooded, either wholly or partially, three times due to threats of war: in 1870 (Franco-Prussian War), in 1914–1918 (World War I), and in 1939–1940 (in the run-up to World War II). The Amsterdam Defence Line never saw active service.

Each of the 10 Dutch Waterlines stamps features a defensive structure that is part of the New Dutch Waterline (top 5 stamps) or the Amsterdam Defence Line (bottom 5 stamps). The vertical image area of ​​each stamp has rounded corners and is divided into two horizontal rectangles. One rectangle contains a color photograph of the relevant defensive structure, connected to an illustration of its ground plan that extends into the other rectangle. The type of defensive structure and the visible part of it are indicated on every stamp. The name and construction period are listed next to each stamp on the top and bottom margins of the sheet. Fragments of 19th-century military maps showing the location of the defensive structures are placed along the edges of the stamp sheet. Various shades of blue and green dominate the stamps and the sheet margins as a reference to the essence of the Dutch Waterlines: the flooding of land.

 

All forts (short summary)

Defensive works: New Dutch Water Line

 

Lunette IV on the Houtense Vlakte, construction period I (1815–1826)

Because the Houtense Vlakte lies higher than the surrounding area, the region could not be flooded. Therefore, starting in 1816, four identical defensive works were built at short distances from each other on this naturally weak point in the water line. The word lunette is derived from the French 'lune', meaning moon. Consequently, a crescent shape can be recognized in the layout of the lunettes.

 

Fort Everdingen, construction period II (1841–1864)

Fort Everdingen, with its large tower fort, was built between 1841 and 1849. Together with Fort Honswijk, it ensured the closure of access to the Lek. This fort also had to defend the three inundation sluices and the inundation canal located close to the fort.

 

Fort bij Vechten, construction period III (1867–1870)

Fort Vechten was built in 1870 as part of the 2nd ring of forts around Utrecht. The fort comprises 16 bomb-proof, earth-covered buildings incorporating 16 million bricks. In 1881, the fort was expanded with a bomb-proof barracks. The fort's artillery blocked off the Houtense Vlakte and the Arnhem-Utrecht railway line. During the mobilization of 1914–1918, reinforced concrete trenches and shelters were added. In 1939–1940, three cast-steel machine-gun casemates were built on the fort's front rampart.

 

Battery near Poederoijen, construction period IV (1870–1886)

This forward battery with bomb-proof barracks was built between 1879 and 1886 in front of the Nieuwedijk. It is situated close to the northern Maasdijk, south of the twin fort, the Batterij onder Brakel. The defensive structure was intended to block access to the Maas: the dammed Maas with its floodplains and the Maasdijk. The battery also provided protection to the sluices required for the inundation of the Bommelerwaard.

 

Work on the Groeneweg, construction period V (1914–1918)

The Werk aan de Groeneweg was constructed between 1914 and 1918 to defend Fort Honswijk. The infantry position consists of a double trench with earthen ramparts, posts for one marksman, and 55 group shelters in the form of somewhat larger pyramid-shaped bunkers.

 

Defenses: Amsterdam Defense Line

 

Fort near Abcoude (1884–1887)

Fort Abcoude was built between 1884 and 1887 as the first fort of the Amsterdam Defence Line. Consisting partly of brick and partly of brick concrete, the fort is an intermediate form between the older brick forts of the New Dutch Water Line and the later concrete forts of the Amsterdam Defence Line. Fort Abcoude served to defence the Utrecht-Amsterdam railway line and the Angstel and Gein rivers, along with the roads running alongside them.

 

Fort Island Pampus (1887–1895)

Fort Island Pampus was built in the Zuiderzee (now IJmeer) between 1887 and 1895. Together with the coastal batteries at Diemerdam and Durgerdam, the fort was intended to defend the city of Amsterdam against attacks from the water. The fort building on Pampus housed two enormous armored turrets, each equipped with two 24 cm caliber cannons. These could fire on enemy ships at a maximum distance of 8 km.

 

Fort bij de Liebrug (1884–1900)

The Fort at Liebrug was tasked with defending the railway, the (now disappeared) towpath canal, and the Amsterdam-Haarlem motorway. Together with Fort Penningsveer and Fort aan de Liede, it formed the Liede Position. Construction of Fort Liebrug began in 1884 and was completed in 1900. The buildings housed two 7 cm caliber cannons and two 6 cm caliber cannons. This fort is smaller than the other forts because the main defensive tasks were performed by the other two forts in the Liede Position. It is one of the few forts situated in open water.

 

Fort at Spijkerboor (1894–1913)

The Fort at Spijkerboor was tasked with defending the Western Beemster Ring Canal, along with its quays and roads. The defensible earthworks were completed in 1894. The bomb-proof building was finished in 1913. At the time, it was one of the most modern and heavily armed forts, equipped with an armored turret housing two twin-barreled 10,5 cm caliber cannons. Four additional 6 cm caliber cannons were positioned at the ends of the fort building.

 

Fort on the Middenweg (1894–1914)

Fort Middenweg defended the Middenweg and the Zuiderweg. These roads were situated higher than the area flooded around the fort. As a result, these roads formed an entrance to Amsterdam. In 1894, the fort was completed as a defensible earthwork, followed later by the construction of the bomb-proof building. This building was not completed until 1914. The buildings housed four 10 cm caliber cannons and two 6 cm caliber cannons. Due to cost-cutting measures, this fort received only one lifting turret building and fewer artillery pieces. To compensate, two additional concrete machine-gun emplacements were placed in the right front rampart.

 

Source: PostNL press release, coehoorn.nl, hollandsewaterlinies.nl

 

About the designer

Bart de Haas (1966, The Hague) studied graphic and typographic design at the Royal Academy of Art in The Hague. After working for various design agencies for a few years, he established himself as an independent graphic and typographic designer in 1993. He has a strong preference for book design, but in the past he has also designed posters, magazines, websites, and visual identities. De Haas has designed books for, among others, Huis Marseille in Amsterdam, the Army Museum Delft, nai010 publishers, Brill Publishers, de Buitenkant, Clio, SUN, THOTH, Vantilt, W-Books, and Waanders. For PostNL, he previously created the stamp series Shipping in the Seventeenth and Eighteenth Centuries (2025) and Birds of Prey in the Netherlands (2024-2026), the stamps 200 Years of the KNRM (2024) and Underwater Nature (2024), the stamp series Underwater World (2021-2023) and Primitive Species (2021-2023), and the stamps Peace, the Highest Value of Humanity (2023), 100 Years of the Dutch Windmill (2023), String Instruments (2022), Dutch Castles (2017), Apple and Pear Varieties in the Netherlands (2016), National Musical Instruments (2014), and Long Live the Forest! (2010).

 

Reason for publication?

The Amsterdam Defence Line was a defensive line situated 15 to 20 kilometers around the centre of the Dutch city of Amsterdam. The Line is 135 kilometers long, contains 45 forts, and was constructed from 1880 to 1920. On September 26, 1995, the Amsterdam Defence Line, together with the New Dutch Water Line, was submitted to UNESCO for inclusion on the World Heritage List, where it was added in its entirety in 1996. In 2021, the New Dutch Water Line was added to the existing World Heritage. Since then, both components have been on the list under the name Dutch Water Defence Line. In 2026, the Amsterdam Defence Line will have been on the UNESCO World Heritage List for 30 years. Could this be the reason for this publication?

Pampus (officially Fort aan het Pampus) is a fortified island in the part of the IJmeer that belongs to the municipality of Gooise Meren. The artificial island was constructed in 1887 as part of the Defence Line of Amsterdam to defend the Pampus shipping channel against attacks from the Zuiderzee.

 

<strong> More info: </strong>

Dutch Waterlines: https://www.hollandsewaterlinies.nl/nl

Menno van Coehoorn Foundation: https://coehoorn.nl/