Lake Constance

Lake Constance (German: Bodensee) is a lake on the Rhine at the northern foot of the Alps,

and consists of three bodies of water: the Obersee ("upper lake"), the Untersee ("lower lake"),

and a connecting stretch of the Rhine, called the Seerhein.

The lake is situated in Germany, Switzerland and Austria near the Alps. Specifically, its

shorelines lie in the German federal states of Bavaria and Baden-Württemberg, the Austrian

federal state of Vorarlberg, and the Swiss cantons of Thurgau and St. Gallen. The Rhine flows

into it from the south following the Austro-Swiss frontier.

Lake Constance was first mentioned by the Roman geographer Pomponius Mela about 43

AD. He noted that the Rhine flows through two lakes, and gave them the Latin names Lacus

Venetus (Obersee) and Lacus Acronius (Untersee). Pliny the Elder used the name Lacus

Brigantinus, after the Roman city of Brigantium (today Bregenz). The lake is also colloquially

known as the Swabian Sea[1]

(das schwäbische Meer, also sometimes Suabian or Svebian

Sea).

The freshwater lake sits at 395 m (1,296 ft) above sea level and is Central Europe's third

largest, after Lake Balaton and Lake Geneva. It is 63 km (39 mi) long, and at its widest point,

nearly 14 km (8.7 mi). It covers approximately 571 km2 (220 sq mi) of total area.

[2] The

greatest depth is 252 metres (827 ft) in the middle of the eastern part (Obersee). Its volume is

approximately 1e10 m3 (1.3×10

10 cu yd). The lake has four parts: the main section, called

Obersee, 476 km2 (184 sq mi); the north section, Überlinger See, 61 km

2 (24 sq mi); the west

section, Untersee, 63 km2 (24 sq mi); and the northwest section, the Zeller See and

Gnadensee. The regulated Rhine flows into the lake in the southeast, through the Obersee, the

city of Konstanz and the Untersee and flows out near Stein am Rhein. Lake Constance

provides fresh water to many cities in south Germany.

Lake Constance was formed by the Rhine Glacier during the ice age and is a zungenbecken

lake. The Rhine, the Bregenzer Ache, and the Dornbirner Ache carry sediments from the Alps

to the lake, thus gradually decreasing the depth and coast line extension of the lake in the

southeast.

The lake was frozen in the years 1077 (?), 1326 (partial), 1378 (partial), 1435, 1465 (partial),

1477 (partial), 1491 (partial?), 1517 (partial), 1571 (partial), 1573, 1600 (partial), 1684, 1695,

1709 (partial), 1795, 1830, 1880 (partial), and 1963.

Approximately 1,000 tonnes (1,100 short tons) of fish were caught by 150 professional

fishermen in 2001 which was below the previous ten year average of 1,200 tonnes (1,300

short tons) per year. The Lake Constance trout (Salmo trutta) was almost extinct in the 1980s

due to pollution, but thanks to protective measures has made a significant return. Lake

Constance was the home of the now extinct species of trout Salvelinus profundus.[3]

as well as

of the Lake Constance whitefish (Coregonus gutturosus).[4]

The lake itself is an important drinking water source for southwestern Germany, called

Bodensee-Wasserversorgung ("Lake Constance Water Supply").[5]

Name After the Council of Constance, the Latin speaking Catholic world gave the lake its current

international name. It was derived from the city name Constantia (Latin name of Konstanz), that, in

turn, was named after a Roman emperor (either Constantius Chlorus or his grandson Constantius II).

The German name, Bodensee, derives on the other hand from the town name Bodman (today's

Bodman-Ludwigshafen) that is situated at a nearby branch of the lake just some 8 km north-west of

Konstanz.

Islands in the lake

The three major islands are:

Mainau Island

Reichenau Island

Lindau