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Posts tagged Zuiderzee

Sediments Near the Coast of the Netherlands

52.3N 4.8E

June 16th, 2010 Category: Sediments

Netherlands - April 14th, 2010

Netherlands - April 14th, 2010

The Netherlands, also known as Holland, are located in northwestern Europe. The country has an area of 16,040 sq mi (41,543 sq km) and a population (2009 est.) of around 16,522,000. The capital is Amsterdam.

The Netherlands’ southern and eastern region consists mostly of plains and a few high ridges; its western and northern region is lower and includes polders on the site of the Zuiderzee and the common delta of the Rhine, Meuse, and Schelde rivers. Coastal areas are almost completely below sea level and are protected by dunes and artificial dikes. Here, sediments are present in these low coastal areas.

Dikes and Lakes in the Netherlands – August 6th, 2009

52.6N 5.4E

August 6th, 2009 Category: Image of the day, Lakes

Netherlands - July 28th, 2009

Netherlands - July 28th, 2009

Netherlands - July 27th, 2009

Netherlands - July 27th, 2009

This ASAR image gives a clear view of the Markermeer and IJsselmeer lakes, formerly the Zuiderzee inlet, in the Netherlands. These two lakes were created by the building of two dikes across the inlet: the Afsluitdijk and the Houtribdijk.

The former is visible as a thin, straight grey line across the dark waters in the upper right quadrant.  The dike, which was constructed between 1927 and 1933, has a length of 32 km (20 miles) and a width of 90 m, at an initial height of 7.25 m above sea-level. It runs from Den Oever on Wieringen in North Holland province, to the village of Zurich in Friesland province.

The Houtribdijk also appears as a narrow line, connecting the cities of Lelystad and Enkhuizen. It is 30 kilometers long and was built between 1963 and 1975. The lake below is the Markermeer, and the other lake above, between the two dikes, is the IJsselmeer.

The color image, captured one day earlier, gives a comparative view of these lakes, showing a brighter green color in the Markermeer. This color difference may be due to a difference in algal concentration or in the suspended sediments – the Markermeer has greater wave action, which causes sediments to be churned up in the water.

Green Waters of the Markermeer, the Netherlands – June 11th, 2009

52.5N 5.2E

June 11th, 2009 Category: Image of the day, Lakes

Netherlands - May 30th, 2009

Netherlands - May 30th, 2009

Sediments and algae color bodies of water near the Dutch coast various shades of brown and green. Particularly striking is the bright yellow-green Markermeer (bottom center), a 700 km² lake in the central Netherlands between North Holland, Flevoland and its larger sibling, the IJsselmeer.

A shallow lake at some 3 to 5 m in depth, it is named after the small former island, now peninsula, of Marken that lies within it. The southwest side of the lake is known as the IJmeer.

The Markermeer used to be part of the Zuiderzee, a saltwater inlet of the North Sea. This inlet was dammed off by the 32 km long Afsluitdijk (Closure Dike) in 1932, turning the Zuiderzee into the freshwater IJsselmeer.

The following years saw the reclamation of extensive tracts of land as large polders in a massive project known as the Zuiderzee Works. Part of the construction of the last polder was building the Houtribdijk, also called Markerwaarddijk, finished in 1976, which hydrologically splits the IJsselmeer in two, the southern section being the Markermeer.

The Markermeer was not originally intended to remain a lake; one of these polders, the Markerwaard, was to occupy the area of the current Markermeer. However, because of changing priorities and doubts about the financial feasibility, the Markerwaard was indefinitely postponed in the 1980s and the Markermeer has since begun to become a valuable ecological and recreational asset of its own.

The Markermeer is used as a freshwater reservoir and a buffer against floodwaters and droughts. In 2003 the Netherlands was hit by drought, and several minor dikes were endangered. Water from the Markermeer was used to keep the area surrounding Amsterdam wet, thereby keeping the dikes safe.

Frisian Islands Chain and Dikes in the Netherlands

May 13th, 2009 Category: Snapshots

The Netherlands - May 12th, 2009

The Netherlands - May 12th, 2009

The West Frisian Islands, in a chain off the coast of the Netherlands, separate the North Sea from the Wadden Sea, an intertidal zone between the continental coast and the islands.

While the North Sea is deeper and appears dark navy blue here, the Wadden Sea has a greenish brown color, as it is a shallow body of water with tidal flats and wetlands rich in biological diversity.

The biggest and most populated of the Frisian Islands is called Texel. It is also the westernmost of this archipelago, and forms the largest natural barrier between the two seas. The dune landscape on Texel is a unique habitat for wildlife.

Below Texel and the Wadden Sea is a body of water formerly known as the  Zuiderzee. After being closed off from the North Sea by a dike, it was separated into two lakes: the IJsselmeer and the Markermeer, which are in turn separated by another dike called the Houtribdijk.

These dikes are visible in the full image as lines where the color of the water changes abruptly from dark brown (Wadden Sea), to dark green (IJsselmeer) to bright green (Markermeer).