evidence: Lake Constance is the second largest (to Lake Geneva) European pre-alpine lake both by area and volume, and the largest lake in Germany. The lake is surrounded by the provinces of Baden.Wurttemberg and Bayern of West Germany in the northern and north-eastern coast and by the territory of Switzerland and Austria in the southern coast. The lake is divided into two parts, the deep "upper lake" and the shallow "lower lake". The Rhein River originated from the Alps flows into the lake at its southeast end and flows out from the west end of the lake. The lake plays a major role as a natural reservoir to make clear the milky turbid inflowing water derived from the glaciers. [...] - Geller, W. & Gude, H. (1989) Lake Constance - the largest German lake. "Limnology in the Federal Republic of Germany" (ed. Lampert, W. & Rothhaupt, K.- O.), pp. 9-17, Carius Druck GmbH, Kiel.