Europe > Netherlands

IJsselmeer: The Largest Lake in Western Europe

lakeIJsselmeer
countryNetherlands
surface area1,100 km2
maximum depth7 m
average depth6 m
lake typeReservoir
catchment area1,400 km2
altitude-0.4 m
volume5 km3
inflowsIJssel, Vechte
outflowsNorth Sea
shore length466 km
settlementsDen Oever
trophic stateEutrophic
dam height19 m
dam year1932

IJsselmeer Information and Facts

Ijsselmeer is a shallow artificial lake, the largest in the Netherlands and in Western Europe. The lake was created in 1932 and was initially part of the Zuider Zee, but was closed off by a man-made dyke.

Geographic Facts

IJsselmeer lies northeast of Amsterdam, surrounded by an open and green landscape. The lake belongs to the Flevoland, North Holland and Friesland provinces and has an average depth of 5-6 meters. It is fed by several rivers, including the Amstel, Rhine, Vecht and the Ijssel, which is a branch of the Rhine. IJsselmeer functions as a major freshwater reserve, and as a source for agriculture and drinking water.

History of its Construction

Before the 13th century the area was governed by a series of freshwater lakes. After a change in local climate and because of the massive peat harvest that occurred around that time, the resistance of fresh water to the salt water weakened.

After this, a massive tidal wave happened, which allowed the sea to encroach and the vegetation to dry off. In the 14th century the area was just a small and shallow branch of the North Sea. During Amsterdam’s Golden Age, when its boats sailed the newly created Zuider Zee towards Scandinavia, the Baltic area and the Orient, the region quickly became known as “The Golden Circle”. The downside of this fact was that the small towns along parts of the lakeshore were nourished with floods, whilst those on the eastern part witnessed an increase in local economy.

At the end of the 18th century the trading declined, so even the wealthier ports were economically stranded. The Zuider Zee supported a batch of fishing villages. In 1891 Cornelis Lely, a Dutch civil engineer and statesman proposed a retaining dyke to solve the flooding crisis in the area. Concrete plans were made after another devastating flood in 1916. Construction work began in 1920 and on the 28th of May 1932 the last gap was closed and the Zuider Zee ceased to exist, being replaced by the IJsselmeer.

The 32-kilometers long Afsluitdijk dam is located 8 meters above sea level. It wasa originally part of a major hydraulic engineering project, which years later led to the reclaiming of the land from the IJsselmeer, reducing the lake’s original surface area. In 1975 the lake further split into two, thanks to the completion of the Houtribdijk. This is located on the southwestern end of the lake and is called Markermeer. The province of Flevoland was established in 1986, and is made up of three polders reclaimed from the lake.

Lake Kefelmeer is a narrow lake located East of IJsselmeer, which gets its water from rivers which contain industrial pollutants from the factories lying upstream. This waste settled into the bottom of the lake, in a thick layer of contaminated sludge. In 2010 attempts have been made in order to restore a normal aquatic environment. An artificial island called IJsseloog was installed on the lake, as a repository for the contaminated water dredged from the bottom of the lake. Once this repository is filled, it will be capped and transformed into a nature reserve.

Tourism and Recreation

The lake is mainly used for transport, fishing, sand mining, wind energy generating and water sports activities. It is considered one of the best lakes for sailing in the country. The lake’s shores can be explored either on foot or by bike. The scenic bike routes lead through rural farmlands, highways, roads and lovely little town streets. There are also a number of nice beaches, perfect for families with little children, since the water is shallow.