Seedamm is the partially artificial causeway and bridge at the most narrow area of Lake Zurich, between Hurden (SZ) and Rapperswil (SG). The Seedamm carries a road and a railway across the lake, with the railway being used by the S5 and S40 lines of the S-Bahn Zürich and by the Südostbahn Voralpen Express.
Geography and location
The Seedam is based on an ice age moraine located between the three Swiss cantons of Schwyz, St. Gallen and Zürich. This morain formed a peninsula protruding from the south shore of the lake and containing the village of Hurden, a small island to the Rapperswil side of the lake, and a section of shallow water dividing Lake Zürich and its upper part (the so-called Obersee). The causeway and bridges span this area of shallow water, are 1 kilometre (0.62 mi) in length and carry a road and a railway line.
To the east of the modern causeway and bridge, there is the Holzbrücke Rapperswil-Hurden (wooden bridge for pedestrians), built in 2001 as a reconstruction of the first bridge between eastern and western lakesides around 1650 B.C.
Whilst the bridge sections of the Seedamm allow smaller vessels to pass under them, the main shipping channel between the lower and upper halves of Lake Zürich now passes through the Hurden ship canal, which was cut through the base of the Hurden peninsular in 1942-3, thus placing the village of Hurden on an artificial island. This canal is spanned by the Sternenbrücke, which also carries both road and railway. This bridge was renewed between March and November 2010 to allow 40 ton trucks to cross the Seedamm.
Around 1650 B.C., a first wooden footbridge led across Lake Zurich followed by several reconstructions at least until late 2nd century AD when the Roman Empire built 6 m wide wooden bridge under Empire Marcus Aurelius (161-180). At Kempraten's Lake Zurich bay, the Roman transshipment harbour for goods was located that have been transported on the Roman streets, on the wooden bridge Rapperswil-Hurden and on the waterway Zurich-Walensee. In 981, a ferry to the Ufenau island is mentioned, probably there was a ferry to the other lakeside, too. By 1358, ferry services between Rapperswil and Hurden are mentioned. Between 1358 and 1360, Rudolf IV, Duke of Austria, built a wooden bridge across the lake that has been used to 1878 – measuring approximately 1,450 metres (4,760 ft) in length and 4 metres (13 ft) wide; 546 oak piles have been installed. A small wooden bridge from Ufenau island to Hurden is mentioned around 1430, so-called «Kilchweg in die Ufenau».
In 1873, the Swiss federal parliament approved the construction of the today's stone causeway and bridge. Construction works have been begun in 1875 and finished in 1878 (in the same year the wooden bridge was broken). The construction costs the sum of 1,462,000 Swiss francs, of wihich 1,100,000 have been paid by the city of Rapperswil. In 1878, the Zürichsee-Gotthardbahn established the railway line from Rapperswil railway station via Seedamm. In 1939 and 1951, the now called Seedamm was reinforced to met the growing demands. At the beginning of the 21st century, an average of 24,000 vehicles and about 75 passenger trains cross the causeway every day.
In 2001, a new wooden footbridge was opened alongside the causeway for the first 840 metres (2,760 ft) meters of the crossing. It was built in quite the same place as the original bridge linking Rapperswil with the nearby bridge chapel (Heilig Hüsli) built in 1551. This connection, for centuries has been part of old pilgrimage routes, the so-called Jakobsweg to the Einsiedeln Abbey.
- "Die Geschichte von Hurden" [The history of Hurden]. http://www.uch.ch/ (in German). Retrieved 18 August 2014.
- "Seedamm wird saniert" [Causeway is being renovated]. Tages-Anzeiger (in German). 9 March 2010. Retrieved 18 August 2014.
- Website Unterwasserarchäologische Projekte Kanton St. Gallen
- Neue Zürcher Zeitung (January 20/21, 2001): Die Brücke auf dem Grund des Zürichsees
- Hurden: History
- Website Holzsteg Rapperswil
- Swiss inventory of cultural property of national and regional significance
- Geneviève Lüscher: Brücken und Wege der Bronzezeit. Schweizerischer Nationalfonds. In: Horizonte, März 2005.
- Beat Eberschweiler: Ur- und frühgeschichtliche Verkehrswege über den Zürichsee: Erste Ergebnisse aus den Taucharchäologischen Untersuchungen beim Seedamm. In: Mitteilungen des Historischen Vereins des Kantons Schwyz, No. 96, Schwyz 2004.
- Hans Rathgeb: Brücken über den See. Arbeitsgemeinschaft Fussgänger-Holzsteg Rapperswil-Hurden, Rapperswil 2001. ISBN 3-9522511-1-9