Waterloopbos: Where Dutch Engineers Learned to Play With The Sea

A quarter of Netherlands lie below the sea level. Most of these low-lying areas are land reclaimed from the sea. The region was originally occupied by the estuaries of three large rivers—the Rhine, the Meuse, and the Scheldt, as well as their tributaries. Starting from the late 16th centuries, the Dutch drained the low-lying areas called polder by building an elaborate drainage system consisting of dikes, canals, and pumping stations. The highlight of this incredible engineering is a series of construction projects called Delta Works, built over a period of four decades, to protect a large area of land around the Rhine-Meuse-Schelde delta from the sea. Along with the Zuiderzee Works—another large land reclamation project on the North Sea—the Delta Works have been declared one of the “Seven Wonders of the Modern World” by the American Society of Civil Engineers.

Waterloopbos

Photo: Photodigitaal.nl/Shutterstock.com

Before construction on Delta Works could commence, engineers sought out a testing ground where they could study the effects of damming rivers, and building dykes, levees and storm surge barriers, on the country’s rivers, estuaries and the surrounding land. A suitable spot was found in the middle of a forest on a polder in northern Flevoland. There, Dutch engineers built scale models of the proposed hydraulic works—dams, sluices, locks, dykes, levees, and storm surge barriers. Water was guided into and out of the miniature locks and sluices brought from a nearby canal. Concrete basins were used to research wave motion. This playground is known as Waterloopbos, meaning Forest of the streams.

Waterloopbos was owned and operated by the Waterloopkundig Laboratorium, a scientific institute specialized in the field of hydraulics and hydraulic engineering, located in Delft. The institute played an important advisory role in the realization of the Delta Works.

Waterloopbos was built in the early 1950s inside Voorsterbos forest, situated between Kraggenburg and Vollenhove. The site met all requirements for an open-air laboratory—the forest floor was about 5 meters lower than the level of the Vollenhover Canal, so that water flowed naturally to the test setups without needing pumps. The soil, compacted by glaciers during the last Ice Age, was firm enough to hold the models without the dangers of subsidence. The level of the outlet basin was again 2 meters lower than the forest floor, facilitating easy discharge of water. Finally, the trees provided protection from wind minimizing its influence on the experiments conducted.

Waterloopbos

Photo: Frans Blok/Shutterstock.com

For the Delta Works project, Waterloopkundig Laboratorium built 35 large scale models simulating the different components of Delta Works. These tests continued for more than twenty years through the 1960s, the 70s and the 80s. Waterloopkundig Laboratorium then began seeking clients from abroad. Over the years, engineers from Nigeria, Turkey and Thailand came to Netherlands to test ports and harbors, rivers and coasts at Waterloopbos. By the 1990s, two-thirds of projects undergoing at Waterloopbos were of foreign clients. In total, more than 200 different studies were conducted at Waterloopbos.

With the development of computer models and software simulation, building of test models became largely unnecessary. The laboratory closed in 1996 and was subsequently abandoned. In 2002, the site was acquired by Natuurmonumenten (the Dutch Nature Preservation Society) with the intention of preserving the many models, now covered in moss and vegetation, that lie scattered throughout the forest. Since then, the site has become a popular spot among enthusiasts. A walking trail was created through the forest running along the various watercourses where the models can still be viewed.