Haringvliet
The Haringvliet is an inland waterway near the coast in the Netherlands ( Zuid-Holland ). The former bay, which has been dammed since 1970, separates the former islands of Voorne-Putten and Hoeksche Waard in the north from Goeree-Overflakkee in the south. The Haringvliet is 28 kilometers long and between 795 and 3,150 meters wide. The mean depth is NAP -8m, the deepest point (at Middelharnis) NAP -39m. The main estuary of the Rhine, called Nieuwe Merwede in the lowest section , and the Meuse jointly reach the North Sea via the Haringvliet and the sluice systems of the barrage . Another body of water in the Rhine-Maas Delta , the Spui , connects the Haringsvliet with the Oude Maas (Hoeksche Waard and Voorne-Putten). The island of Tiengemeten is located in the Haringvliet .
Origin and changes
Before 1200, Voorne and Flakkee were still a single island. Then in 1216 a storm surge tore the bay of the Haringvliet into the country, and later the Hollands Diep was formed further inland . At that time the Haringvliet was also called Flakkee , and it wasn't until the 19th century that it got its current name. In 1970 the Haringvliet was part of the Delta Plan with the Haringvlietdam separated from the North Sea and thus a part of the lowermost Rhine run that since only reaches the sea at the barrage.
Environmental situation and countermeasures
The Haringvliet was softened by the dyke and the tides ceased. The marine to brackish ecosystem was lost. Because the Biesbosch in the confluence of the Rhine and Meuse was no longer regularly flooded, the reed belt perished. Various fish species almost completely disappeared from the affected waters. The discharge of organic waste water from intensive livestock farming in Noord-Brabant led to blue-green algae poisoning , which killed many birds.
In 1991, investigations were initiated into how opening the current gates would affect the Haringvliet. If one wanted to restore typical conditions for a river delta, the flood gates , like on the Oosterschelde , should only be closed at high tide. In 2003, the cabinet decided on the so-called gap solution , which means that when the tide comes in, the gates are only opened a gap to create a transition area between salt and fresh water. Interest groups are demanding compensation from the state in order to adapt Zeeland's freshwater infrastructure, which has now been built, to the return of the tides. Starting in 2018, the flood gates will be opened in gaps, accompanied by environmental studies. With the partial opening it is hoped to be able to create a brackish water biotope again, to reduce the sludge deposits and to improve the water quality.
Previously, freshwater extraction points for agriculture and drinking water production had to be relocated, as well as a monitoring network and protective structures against flooding. The salt water must not reach more than one line from the mouth of the Spu to Middelharnis. A minimum water level of NAP = 0 must be maintained for the Moerdijk gauge. As before, however, when the water in the Rhine is low (below 1100 m³ / s at the Lobith gauge), the barrage is closed to allow the water of the Nieuwe Merwede and the Maas to enter the main shipping route, the Nieuwe Waterweg .
Web links
- Haringvliet Rijkswaterstaat (Dutch)
Individual evidence
- ↑ http://www.rijkswaterstaat.nl/water/projectenoverzicht/haringvliet-haringvlietsluizen-op-een-kier/index.aspx
source
- Haringsvliet Actuele informatie - Rijkswaterstaat: Haringsvliet lock