Lake Constance

Map of the Bodensee; Schweiz is Switzerland, Deutschland is Germany, and Österreich is Austria.

Lake Constance or Lake of Constance (German and Alemannic Bodensee, French Lac de Constance) is a large lake on the Rhine between Germany, Switzerland, and Austria. It lies approximately at .

Lake Constance was first mentioned by the Roman geographer Pomponius Mela about 43 BCE. He noted that the Rhine flows through two lakes, and gave them the Latin names Lacus Venetus (today Obersee) and Lacus Acronius (today Untersee). Pliny the Elder used the name Lacus Brigantinus, after the Roman city of Brigantium (today Bregenz). The lake is also known as the Swabian Sea (das Schwäbische Meer).

Sunset at Lake Constance

The freshwater lake sits at 395 m above sea level and is Central Europe's third largest, after Lake Balaton and Lake Geneva. It is 67 km (41 mi) long, and at its widest point, nearly 13 km (8 mi). It covers approximately 539 km² (208 mi²) of total area[1]. The greatest depth is 252 m in the middle of the eastern part (Obersee). Its volume is approximately 55 km³. The lake has four parts: Obersee (main, 476 km²), Überlinger See (north, 61 km²), Untersee (west, 63 km²), and the Zeller See and Gnadensee (northwest). 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. The Rhine, the Bregenzer Ache, and the Dornbirner Ache carry sediments from the Alps to the lake, thus gradually decreasing the depth of the lake in the southeast.

Approximately 1000 tons of fish were caught by 150 professional fishermen in 2001 which was below the previous ten year average of 1200 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.

Car ferries link Romanshorn, Switzerland to Friedrichshafen, and Konstanz to Meersburg.

Geographic oddity

There is no legally binding agreement as to where the boundaries lie between Switzerland, Germany and Austria where these three countries meet in Lake Constance. While Switzerland holds the view that the border runs through the middle of the lake, Austria is of the opinion that the lake stands in condominium of all the states on its banks. Germany holds no unambiguous opinion. Legal questions pertaining to ship transport and fishing are regulated in separate treaties.

Disputes naturally arise. One concerns a boat house which was moored in two states, another concerns the rights to fish in the Bay of Bregenz. In relation to the latter, an Austrian family was of the opinion that it alone had the right to fish in broad portions of the bay. This however was accepted neither by the Austrian courts nor by the organs and courts of the other states [2].

Recent Floods

* The so-called "flood of the century" in May or June 1999 raised the level about 2 metres above normal, flooding harbors, and many shoreline buildings and hotels.
* In late August 2005, heavy rains raised the level over 70 cm in a few days. The rains caused widespread flooding and washed out highways, railroads; those in western Austria were still closed on September 9.