It is a historical defense system whereby water was used to stop the enemy from advancing. Large sections of land were flooded. Just 40 cm of water was enough to stop the enemy. Too much to try and wade through with all military equipment and not sufficient to use boats. Only dykes were passable and therefore easy to defend.
The waterline was first used on a large scale in the 17th century. This was a century of great economic and cultural prosperity for the Dutch. Trading with the Far East made many people rich and it was also the era of famous painters such as Rembrandt and Vermeer. It brought on the jealousy of the king of France, Louis XIV and he and some small German states declared war on Holland. In 1672 enemy troops marched west in the direction of Amsterdam. The Dutch army was totally unprepared. Most of the military funds were used for the navy as the merchant fleet played such an important part in the economy. The French army advanced at great speed and one town after another was overrun and plundered. They had to be stopped and Holland decided to use water as a weapon. There was no time to think and a large section of land was rapidly submerged in water by (more or less) controlled flooding. It ran from Muiden in the north to Gorinchem with castle Loevestein in the south. Inbetween, at crucial points, redoubts were set up, sometimes supported by armed vessels. Head of the Dutch army was the young Prince Willem III and he and his men stood their ground. The towns which were situated outside the protection of the waterline had a tough time. Food supplies, horses, hay and grain were confiscated by the enemy. Often whole villages were raised to the ground and many people lost their lives. A flaw in the system came to light in the winter of 1672 when the water started to freeze over. French soldiers marched over the ice without any resistance. Luckily thaw set in soon afterwards and the French had to withdraw again. In the end they gave up altogether and retreated. The waterline had worked, Holland was saved. But what was left behind was a desolate country. It had been a disastrous year.
With the enemy gone the water needed to be drained from the land and locks, bridges and windmills restored. Now it was time to install a coherent waterline against future invasions. A military engineer by the name of Menno van Coehoorn was appointed to design the waterline and to reinforce a number of walled towns. All walled towns were laid out conform a concept of ramparts and bastions. Sections of agricultural land were designated to be flooded if necessary. In addition, a whole new fortress was built: Fort Wierickerschans. This waterline served it ‘s purpose until 1816 after which new ways of warfare made it necessary to design a complete new waterline with a large number of fortresses. This New Dutch Waterline was built more to the east so in future, the city of Utrecht was protected.
Even three hundred and fifty years later the Old Dutch Waterline is still much in place. It is not easily recognized as much of it lies hidden in the countryside. The full extension comes only to life when put into action and the land is flooded. With its walled towns and attractive countryside the line offers excellent opportunities for recreation. Lots of waterways to boat and narrow dykes and special bike-lanes to go out cycling. For the walkers a special long-distance Waterline route has been set out. The Old Dutch Waterline should be treasured and therefore protected by means of a monumental status. The Green Heart Foundation (Stichting Groene Hart) appointed itself to curator of the Old Dutch Waterline and has published a number of books on the subject. With exhibitions, cultural events, re-enactments and a video, the foundation tries to bring this military monument to the attention of the general public and create awareness with the politicians so that it will be saved for future generations.