Lake Zug

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Lake Zug
Lake Zug from Rigi.jpg
View of Lake Zug from Rigi , shadow of Rigi Kulm
Geographical location Central Switzerland
Tributaries Lorze
Drain Lorze
Places on the shore Zug , Cham , Arth , Walchwil
Location close to the shore Rotkreuz ZG , Baar ZG , Küssnacht SZ
Data
Coordinates 679 404  /  220821 coordinates: 47 ° 8 '  N , 8 ° 29'  O ; CH1903:  679404  /  220821
Zugersee (Switzerland)
Lake Zug
Altitude above sea level 413  m above sea level M.
surface 38.3 km²
length 13.7 km
width 4.6 km
volume 3.21 km³
scope 42.328 km
Maximum depth 198 m
BFS no. : 9175
Map Zugersee.png
Template: Infobox Lake / Maintenance / PROOF LAKE WIDTH

The Lake Zug is located in central Switzerland at an altitude of 413  m above sea level. M. , has an area of ​​38.41 km² and a maximum depth of 198 m. With its maximum length of 13.7 km and its maximum width of 4.6 km, it is the tenth largest lake in Switzerland. At its narrowest point between Chiemen and Lothenbach, the banks are about 1000 m apart. Together with the lake area, Lake Zug has a catchment area of 246 km².

The main inflow and outflow is the Lorze , which flows through Lake Zug for a short stretch to the north. It flows into the lake west of Zug and leaves it 1.5 km away at Cham . Lake Zug is divided by the wooded Chiemen peninsula into the mountain-framed and deep Obersee in the south and the flat and wide Untersee in the north.

location

The canton capital Zug is on the north-eastern shore of the lake , while the Schwyz municipality of Arth is in the south . The largest neighboring canton of Zug in the north includes 24.32 km² of the lake, followed by Schwyz in the south with a share of 11.67 km² and a small part of the canton of Lucerne in the west near Chiemen with a share of 2.42 km² on the lake.

ecology

Annual mean values ​​of the phosphorus content in Lake Zug in µg / l
Lake Zug with the Rigi in the background

Until the beginning of the 20th century, Lake Zug was still oligotrophic (low in nutrients), but for a long time it was one of the most polluted lakes in Switzerland due to increasing eutrophication . Even today it shows a high nutrient load, even if the water quality is gradually improving. The excess of phosphorus leads to strong algae growth in the upper layers of the lake, which in turn cause oxygen deficiency in the deep water through their aerobic degradation after they die. Due to the above-average depth in the Obersee, this process is intensified because the water there is cut off from the atmosphere for a long time. The main reasons for the poor water quality nowadays are the long retention time of the water in the basin and the lack of mixing due to the poor flow situation of the Lorze. The water of the 3.18 km³ lake therefore has an average retention time of 14.5 years. In the past, the phosphorus pollution was mainly caused by the phosphates contained in the detergent , which reached the lake unfiltered through the sewage. To improve the situation, the city of Zug decided to build a two-stage sewage treatment plant in 1953, which was followed in 1968 by a third treatment stage that also filtered out phosphates from the wastewater. Since the sewage from the other municipalities on the lake continued to flow into the lake, the Cantonal Council of Zug passed the Law on Waters (GewG) in 1969 , which provided for the entire sewer system around the lake to be connected with a loop and the sewage in to manage a regional sewage treatment plant in Schönau below Cham. Since its completion in 1977, the Friesencham plant has been treating wastewater from 14 communities. It is supported by the water protection association of the Zugersee-Küssnachtersee-Ägerisee region (GVRZ) founded in 1970 . However, due to the increased use of fertilizers in agriculture, large amounts of phosphorus soon found their way back into Lake Zug through washouts, as a result of which in September 1990 the law on waters was expanded to include new guidelines for agriculture.

Flora and fauna

There are currently 32 species of fish in Lake Zug. Of these, the whitefish , the Zug red chalk (an autochthonous species of the char ), the perch ( river perch ) and the pike are of economic importance as food fish . The red chalk, first mentioned in a document in 1281, also served as a means of payment in the region until the late Middle Ages . The sharply reduced catch quotas in the course of the 20th century were able to be increased again slightly as a result of the measures introduced. In addition to efforts to improve water quality, food fish are artificially reared and released in fish hatcheries and the natural spawning zones of the fish are maintained. The neighboring cantons of Zug, Schwyz and Lucerne are legally obliged by the intercantonal concordat on fishing in Lake Zug of April 1, 1970 to manage Lake Zug in a sustainable manner .

Most of the shore area of ​​Lake Zug is built up. The reed stocks have declined sharply since the beginning of the 20th century. You can only find them on the north bank and on the northern part of the west bank. About a third of the shallow water zone is covered with plants such as algae , moss , ferns and horsetail . The bank and shallow water area slowly silts up due to the incomplete decomposition of dead plants, leaving behind peat bogs that were previously used intensively by the residents.

Trivia

A memorial plaque erected on March 16, 2019 in Zug's Unteraltstadt commemorates the emergency landing of a bomber on Lake Zug during the Second World War . Its commander had his crew disembark from the damaged aircraft on March 16, 1944 after turning around in front of the Alps via Baar and flew the landing on the lake alone. One of the nine crew members did not survive the jump. The aircraft, named Lonesome Polecat , was recovered from the lake in 1952, shown in various Swiss cities and scrapped in St. Moritz in 1972.

See also

Web links

Commons : Zugersee  - collection of images, videos and audio files

Individual evidence

  1. ↑ a b c d e Seen (Federal Office for the Environment FOEN). Retrieved January 19, 2020 .
  2. ↑ Swiss soldier, June 2019, page 38