IJsselmeer

(for map see Zuiderzee Works)

The IJsselmeer (IJssel-lake) is a shallow lake of some 1250 km² in the central Netherlands bordering the provinces of Flevoland, North Holland and Friesland, with an average depth of 5 to 6 m. It is named after the IJssel river that drains into it via a smaller lake, the Ketelmeer.

The IJsselmeer was created in 1932 when an inland sea, the Zuiderzee, was closed by a 32 km dam, the Afsluitdijk. This was part of a major hydraulic engineering project known as the Zuiderzee Works, that would in later years lead to the reclaiming of land from the IJsselmeer, thereby diminishing the size of the lake and in 1975 the IJsselmeer was furthermore split in two by the completion of the Houtribdijk, now also called Markerwaarddijk, which runs from Enkhuizen southeast to Lelystad. This former southern part of the IJsselmeer is now the hydrologically separate Markermeer.

The IJsselmeer functions as a major fresh water reserve, serving as a source for agriculture and drinking water. It also offers plenty of opportunities for various recreational activities.

The province of Flevoland was created in 1986 from the polders reclaimed from the IJsselmeer.