'' are visible. Yellow: German state of
Baden-Württemberg, green: Swiss canton of
Thurgau, red: Swiss
Canton of Schaffhausen, red line:
Germany–Switzerland border volcanoes
Hohentwiel (front) and
Hohenstoffeln (back) and
Zeller See , with Rheinsee
in the front and Gnadensee'' in the back The Lower Lake Constance measures and is situated about lower than the
Obersee. The
Romans called it
Lacus Acronius. In the Middle Ages, the Upper Lake was called
Bodamicus Lacus, or
Bodensee in German. At some point in time, this term began to include the Lower Lake, and a new term "Upper Lake" (in German:
Obersee), was introduced for the larger lake. The main tributaries are the
Seerhein and
Radolfzeller Aach. The source of the latter is the
Aachtopf, a
karst spring whose waters mainly derive from the
Danube Sinkhole, making the
Danube indirectly a tributary of
Untersee and the Rhine, respectively. The landscape surrounding the Untersee is very diverse. The Untersee contains two islands:
Reichenau and
Werd (near the transition to the
High Rhine). In the northeast is the peninsula
Bodanrück; in the northwest, the
Hegau lowlands with the peninsula
Mettnau; in the west, the peninsula
Höri, with a mountain called
Schiener Berg, and in the south, the
Seerücken, which reaches more than feet above the Untersee near
Berlingen. Bordering the Lower Lake Constance are the
Swiss cantons of
Thurgau and
Schaffhausen and the
German state of
Baden-Württemberg. In contrast to the
Upper Lake, the border between Germany and Switzerland across the Lower Lake is well defined. Municipalities on the Swiss side are
Gottlieben,
Ermatingen,
Salenstein,
Berlingen,
Steckborn,
Mammern,
Eschenz and
Stein am Rhein. Municipalities on the German side are
Öhningen,
Gaienhofen,
Moos am Bodensee,
Radolfzell,
Reichenau,
Allensbach and
Constance. Three parts in the north of Lower Lake, surrounded by German territory, have names of their own:
Zeller See (),
Gnadensee () and
Markelfinger Winkel (). The part in the south, which borders Switzerland, is called
Rheinsee ().
Zeller See The
Zeller See is the part between the
Mettnau peninsula in the north, the
Höri peninsula in the south and the
Island of Reichenau in the east. To the west lies the estuary of the
Radolfzeller Aach and the
Hegau. In the east, there is a small island called
Liebesinsel () close to the Mettnau peninsula.
Gnadensee The
Gnadensee extends from
Allensbach in the north and the Island of Reichenau in the south, from the tip of Mettnau in the west to the Reichenau
causeway with its well-visible
poplar avenue in the east. According to legend, the name
Gnade () of the lake comes from the time when the
court house was located on the Island of Reichenau. If a defendant was sentenced to death, the execution of the sentence could not be carried out on the island, but only on the mainland because the island was "holy ground". Therefore, the condemned man was brought by boat to the mainland in the direction of Allensbach, where the sentence could be
Gnade. Now, if the abbot wanted to pardon the condemned, he would ring a bell before the offender arrived on the other shore. This signaled to the executioner on the mainland, that prisoner had been pardoned. However, this story is unlikely to be true. A more probable theory is that the lake is named after Maria, "Our Lady of Mercy", as the church of the abbey on the island was dedicated to St. Mary and St. Mark. The town name
Frauenfeld in neighbouring
canton of Thurgau can be similarly explained.
Markelfinger Winkel The
Markelfingen Winkel is the western end of the Gnadensee, between Markelfingen in the north, Radolfzell in the west and the Mettnau peninsula in the south. Its eastern boundary is at the level of the summit
Mettnauspitze. With its maximum water depth of 16 m, the Markelfingen Winkel is the shallowest part of the lake. It has a tributary: the Mühlbach, which drains the
Mindelsee.
Rheinsee The mainly Swiss section of the lake south of the Island of Reichenau and its southwestern arm is known as
Rheinsee (), not to be confused with
Seerhein (), which is the Upper and Lower Lakes connecting segment of the river Rhine). It is called the
Seerhein because the current of the river follows exactly this path through the lake to the effluent of Lower Lake Constance in the Swiss town of
Stein am Rhein, where the
High Rhine starts. At the end of the lake, there are three small islands, called the
Werd Islands. Where the
Seerhein flows into the
Rheinsee there is the island of
Triboldingerbohl. There used to be another island called
Entlibühl. The nature reserve
Wollmatinger Ried is also located in this area. The
border between Germany and Switzerland follows
Rheinsee in east-west direction. == Transport ==