Lake Constance, known locally as the Bodensee, is a major freshwater reservoir situated at the northern edge of the Alps in Central Europe. This expansive body of water acts as a natural hub for the region, connecting the countries that share its shoreline. Examining the lake’s surface area, depth profile, and international borders provides a complete picture of its scale.
Surface Area and Overall Volume
Lake Constance covers a total surface area of approximately 536 square kilometers, making it one of the largest lakes in Central Europe. The Bodensee is the third-largest freshwater lake by surface area in the region, behind Lake Geneva and Lake Balaton. It stretches about 63 kilometers in length and nearly 14 kilometers at its widest point.
The total volume of water contained within this basin is estimated at around 48 cubic kilometers. By volume, Lake Constance ranks as the second-largest in Central Europe, storing a large amount of freshwater. The primary source of this inflow is the Alpine Rhine river, which carries glacial meltwater and sediment into the southeastern end of the lake. This volume results in a residence time of several years before the water is fully exchanged.
Depth and Underwater Topography
The vertical dimensions of Lake Constance reveal a deep, glacially carved basin with a varied underwater landscape. Its average depth is 90 meters. The maximum measured depth plunges to 251 meters, a point located roughly in the middle of the Obersee, or Upper Lake. This deepest point highlights the geological forces that shaped the lake during the last Ice Age.
The lake is naturally divided into two main sections: the larger Obersee and the smaller Untersee, which are connected by a short stretch of the Rhine river. The Upper Lake accounts for the vast majority of the lake’s size, covering about 473 square kilometers. The Lower Lake, the Untersee, is significantly shallower and smaller, with a surface area of about 63 square kilometers.
International Boundaries and Shoreline Length
The shores of Lake Constance are shared by three European nations: Germany, Switzerland, and Austria. Germany claims the longest portion of the shoreline, with Switzerland and Austria sharing the remainder. The total perimeter of the lake measures approximately 273 kilometers. This extensive shoreline is a significant area for regional commerce and tourism.
A complex aspect of the lake’s geography is the absence of a formally agreed-upon international border across the main body of the Obersee. Switzerland maintains that the border should follow the median line, dividing the lake equally among the bordering states. Austria considers the main lake to be a “Condominium,” or an area of shared sovereignty among all three nations. Germany has not taken a definitive stance on the matter, resulting in a unique legal status where the deepest parts of the lake are not assigned to a single country.