The Grevelingen or Grevelingenmeer (

Lake A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from ...

Grevelingen) is a closed off part of the

Rhine The Rhine ( ) is one of the List of rivers of Europe, major rivers in Europe. The river begins in the Swiss canton of Graubünden in the southeastern Swiss Alps. It forms part of the Swiss-Liechtenstein border, then part of the Austria–Swit ...

Meuse The Meuse or Maas is a major European river, rising in France and flowing through Belgium and the Netherlands before draining into the North Sea from the Rhine–Meuse–Scheldt delta. It has a total length of . History From 1301, the upper ...

estuary An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime enviro ...

on the

border Borders are generally defined as geography, geographical boundaries, imposed either by features such as oceans and terrain, or by polity, political entities such as governments, sovereign states, federated states, and other administrative divisio ...

of the Dutch

province A province is an administrative division within a country or sovereign state, state. The term derives from the ancient Roman , which was the major territorial and administrative unit of the Roman Empire, Roman Empire's territorial possessions ou ...

s of

South Holland South Holland ( ) is a province of the Netherlands with a population of over 3.8 million as of January 2023 and a population density of about , making it the country's most populous province and one of the world's most densely populated areas. ...

and

Zeeland Zeeland (; ), historically known in English by the Endonym and exonym, exonym Zealand, is the westernmost and least populous province of the Netherlands. The province, located in the southwest of the country, borders North Brabant to the east ...

. It is situated between the islands of

Goeree-Overflakkee Goeree-Overflakkee () is the southernmost river delta, delta island of the Provinces of the Netherlands, province of South Holland, Netherlands. It is separated from Voorne-Putten and Hoeksche Waard by the Haringvliet, from the mainland of North ...

(South Holland) and Schouwen-Duiveland (Zeeland) and was closed off as part of the

Delta Works The Delta Works () is a series of construction projects in the southwest of the Netherlands to protect a large area of land around the Rhine–Meuse–Scheldt delta from the sea. Constructed between 1954 and 1997, the works consist of dams, slu ...

, a huge engineering project designed to protect the southwestern part of the Netherlands from flooding. The Brouwersdam, a dike connecting the two islands on the west, closes off the Grevelingen from the

North Sea The North Sea lies between Great Britain, Denmark, Norway, Germany, the Netherlands, Belgium, and France. A sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian Se ...

. The Grevelingendam, the dike on the east, blocks the inflow of the Rhine and Meuse water. Since its closure in 1971, the saltwater of the Grevelingen slowly started to become brackish due to rainwater and excess

polder A polder () is a low-lying tract of land that forms an artificial hydrology, hydrological entity, enclosed by embankments known as levee, dikes. The three types of polder are: # Land reclamation, Land reclaimed from a body of water, such as a ...

water from the islands, but the Dutch changed their mind and decided that they wanted to preserve the saline

biotope A biotope is an area of uniform environmental conditions providing a living place for a specific assemblage of flora (plants), plants and fauna (animals), animals. ''Biotope'' is almost synonymous with the term habitat (ecology), "habitat", which ...

. Therefore, in 1978 a sluice was created under the Brouwersdam, partially restoring and maintaining the saline character of the Grevelingen. Nevertheless, the water body life remains affected by the changes in water salinity, in the transport of sediments, and by a deficit in oxygen in deep water, caused by the levee since 1971.

Benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from the Ancient Greek word (), meaning "the depths". ...

life (

mussel Mussel () is the common name used for members of several families of bivalve molluscs, from saltwater and Freshwater bivalve, freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other ...

oyster Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but no ...

s and many fixed organisms) is rich in the shallow waters in the

photic zone The photic zone (or euphotic zone, epipelagic zone, or sunlight zone) is the uppermost layer of a body of water that receives sunlight, allowing phytoplankton to perform photosynthesis. It undergoes a series of physical, chemical, and biological ...

, but the deep sediments are less conducive to marine life, and fishes in open water are rarely observed during diving. The Brouwerssluis is open all year round except during storm floods. Brouwerssluis is the home of a seal colony subsisting on fish transported by the

seawater Seawater, or sea water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has approximat ...

stream entering the water body during high

tide Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables ...

. Connexxion bus service 104 crosses the Brouwersdam, bus service 133 (and others) the Grevelingendam. The Grevelingenmeer is the largest saltwater water body in Europe and a popular place for holidays and water sports (

sailing Sailing employs the wind—acting on sails, wingsails or kites—to propel a craft on the surface of the ''water'' (sailing ship, sailboat, raft, Windsurfing, windsurfer, or Kitesurfing, kitesurfer), on ''ice'' (iceboat) or on ''land'' (Land sa ...

surfing Surfing is a surface water sport in which an individual, a surfer (or two in tandem surfing), uses a board to ride on the forward section, or face, of a moving wave of water, which usually carries the surfer towards the shore. Waves suita ...

diving Diving most often refers to: * Diving (sport), the sport of jumping into deep water * Underwater diving, human activity underwater for recreational or occupational purposes Diving or Dive may also refer to: Sports * Dive (American football), ...

Trivia

Professional freestyle windsurfer Steven Van Broeckhoven refers to the Grevelingenmeer as his homespot.

References

External links

Map of area
Lakes of the Netherlands Rhine–Meuse–Scheldt delta Landforms of South Holland Landforms of Zeeland Ramsar sites in the Netherlands Natura 2000 in the Netherlands Goeree-Overflakkee Schouwen-Duiveland {{Zeeland-geo-stub