Greifensee (body of water)
|The lake in all its length and breadth from the south|
|Geographical location||Canton Zurich|
|Tributaries||Aa , Aabach , Aschbach , Dorfbach , Rohrbach|
|Places on the shore||Uster|
|Coordinates||693 817 / 245030|
|Altitude above sea level||435 m above sea level M.|
|Maximum depth||32.3 m|
|Middle deep||17.6 m|
|Catchment area||168.7 km²|
|BFS no. : 9040|
The Greifensee is located in the Canton of Zurich in Switzerland and by the Pfannenstiel chain from Zurich separated. With a length of 6 kilometers and a maximum width of 1.6 kilometers, it is the second largest lake in the canton . Its shape is similar to that of a fish: In the middle, the lake tapers to a width of less than 800 meters.
The catchment area of the Greifensee is 160 km². The main tributaries are the Ustermer Aa (outflow of the Pfäffikersee ) and the Aabach . The runoff is the Glatt , which drains a large part of the Zurich Oberland.
Location and origin
The lake is located in a hilly landscape formed by the Linth glacier in a hollow formed during the last ice age . The Pfannenstiel chain rises to the west, and the Zurich Oberland begins in the east . Despite these hills on either side, the banks are flat. There are no islands in Greifensee.
Originally, the Greifensee was dammed on a terminal moraine near Dübendorf . Due to siltation and amelioration , the lake has lost more and more of its original size since its formation. Moors and plains in the north and south bear witness to this millennia-long development.
The old town of Greifensee is the only settlement right on the lake. The places Niederuster, Schwerzenbach , Maur and Fällanden are close to the lake, a little further away from the water are the towns of Uster and Mönchaltorf .
The shores of the lake are under nature protection. The banks are not built on and are only accessible in a few places. So could many places in the reeds , the flat moore and Ried reported with a rich fauna and flora get: Around the lake there are 400 plant species in the lake and its tributaries 19 species of fish. The nature reserves are important for the bird world . More than 120 migratory bird species have been identified. The Greifensee Foundation is responsible for the supervision and information of the nature reserve .
In the reed area at the southeast end, about 200 meters from the bank, there is a viewing platform to the right of the Aabach ( coordinates ). The platform of the "observation tower" is 4.5 meters high and is used for bird watching. It belongs to the nearby Silberweide nature station of the Greifensee Foundation. The wooden structure originally built in 1997 was renewed in 2015 using local larch wood.
Due to the heavy population and agricultural use of the region around the lake, a very high concentration of phosphorus was found in the water for a long time , which harmed the biodiversity in the lake. Algae and stench kept people away. Since 1970, the situation has been markedly improved by ventilation and reducing the amount of phosphate discharged. Sewage treatment plants have existed in the entire catchment area since 1972 .
However, the values are still more than double the target value. Around 10 tons of phosphorus enter the lake every year. The oxygen content in the water is often too low, especially in the summer months. In years with hot summers, fish died repeatedly. Whitefish and lake trout in particular suffer from excessively high temperatures and the resulting algae. The cantonal office for waste, water, energy and air therefore planned to install a lake water ventilation system west of the Aa estuary - as is already in use in the neighboring lake Pfäffikersee and other small Zurich lakes. In spring 2009 a ventilation system was installed which enriches water from a depth of 12.5 meters with atmospheric oxygen by means of two diffusers. This system is supposed to create a layer over an area of around one square kilometer that will provide the fish with sufficient oxygen and favorable temperature conditions even in summer.
The nature around the lake and the quiet location attract numerous people looking for relaxation. Popular hiking and cycling trails lead all around. Private motor boats are prohibited on the Greifensee. However, the passenger ships of the Greifensee shipping cooperative offer round trips and operate a scheduled service between Maur and Niederuster. In addition, rowing boats, stand-up paddlers and some sailing ships use the idyll. There are several bathing establishments available for bathers.
There are various campsites on the west bank. In Fällanden there is a youth hostel near the water .
Even today (2012) a professional fisherman earns his living on the lake.
The Greifensee run takes place annually at the beginning of autumn . This half marathon leads from Uster around the lake.
Various prehistoric pile dwellings were found on the eastern and northern banks as early as the second half of the 19th century . The first bank settlements were in the Mesolithic from around 8000 BC. Inhabited. They are therefore among the oldest archaeological sites in the Canton of Zurich. The prehistoric site of Storen / Wildsberg on the right bank in front of the city of Greifensee is a UNESCO World Heritage Site. Prehistoric pile dwellings around the Alps .
When Greifensee Castle was built in the 12th century , the lake was still called Glattsee . It was given its current name 100 years later.
By correcting the Glatt and the weir that was added in 1891, the mean level of the lake was reduced by around 80 centimeters. Regulation was important at the time so that the industrial companies on the Glatt had sufficient water even in dry times.
A scheduled ship has been connecting the western and eastern banks since 1890. On April 3, 1892, an overloaded ship capsized. Four people drowned. The new steamship "Greif" from 1895 was powered by gasoline from 1916 onwards. Restored, it steams across the lake, again powered by the original engine from 1895. It is the oldest steamship in Switzerland. In 1933 the first motor ship, the MS “Heimat”, went into operation. Today (2017) the Greifensee shipping cooperative has three motor ships.
In 1941 the lake and its banks were placed under nature protection.
On April 24, 1944, a shot down American B-17 bomber of the United States Air Force fell into the lake, killing several crew members.
In 1994 the Government Council of the Canton of Zurich issued a revised Protection Ordinance.
Seegfrörni on the Greifensee in February 2012
List of lakes in the canton of Zurich
- Greifensee Foundation
- Association for the protection of the Greifensee VSG
- Diethelm Zimmermann: Greifensee (lake). In: Historical Lexicon of Switzerland .
- ↑ a b c d e f Greifensee. (PDF; 84 kB) In: Canton of Zurich. Office for Water, Energy and Air, Department of Water Protection, accessed on February 25, 2013 .
- ^ A b c Charles Knapp, Maurice Borel, Victor Attinger, Heinrich Brunner, Société neuchâteloise de geographie (editor): Geographical Lexicon of Switzerland . Volume 2: Emmenholz - Kraialppass . Verlag Gebrüder Attinger, Neuenburg 1904, p. 438 f., Keyword Greifensee ( scan of the lexicon page ).
- ^ Lakes (Federal Office for the Environment FOEN). Retrieved January 18, 2020 .
- ↑ New observation tower for nature lovers. In: Greifensee Foundation. July 22, 2015, archived from the original on March 4, 2016 ; accessed on March 18, 2018 .
- ↑ Media release from the building department of the Canton of Zurich of October 27, 2009: Greifensee breathes a sigh of relief
- ↑ Media release from the building department of the Canton of Zurich from January 11, 2008: Greifensee: Ventilation expands the fish's habitat
- ↑ The history of Greifensee shipping and its fleet , sgg- Greifensee.ch ( Memento of the original of February 14, 2009 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ www.inware.ch: Ship rentals . Retrieved December 3, 2017 .
- ↑ A US bomber in Greifensee , Metropol, September 26, 2000 ( Memento of the original from January 7, 2009 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 660 kB)