Fulbert tunnel

from Wikipedia, the free encyclopedia

Coordinates: 50 ° 24 ′ 3.4 ″  N , 7 ° 16 ′ 0 ″  E

Delius tunnel entrance

The Fulbert tunnel is a medieval water solution tunnel on the Laacher See . It was raised to stabilize the water level and to gain land on the lake shore .

The Swisttaler geodesist and archaeologist Klaus Grewe assumes that a dendrochronologically proven drought in the years from 1164 was the prerequisite for the tunnel construction. Grewe therefore named the tunnel after Abbot Fulbert (1152 to 1177). According to Grewe, the tunnel should protect the monastery under construction from flooding. Newer sources assume an origin already during the Roman rule.

description

The lake is located in the caldera of the Laacher volcano and has no natural runoff. The water level therefore mainly depends on the amount of precipitation and fluctuated greatly. With the tunnel as an overflow, a maximum water level could be maintained.

The 880 m long, around 3 m high and at least 1.30 m wide tunnel leads south from Laacher See through the surrounding mountain ring. The water flows over the Laachgraben into the Laacher mill pond near Mendig , which is still in use today .

The tunnel was driven in the so-called Kanat construction method , i.e. H. On the defined axis of the tunnel, around 30 vertical light holes were first sunk up to the intended bottom, from which the drive then took place in both directions. This technique was demonstrably known to the Romans.

history

The tunnel verbrach mid-13th century and was under Abbot Dietrich II. Of Lehmen wiederaufgewältigt , as is known from received invoices.

After the secularization of the monastery in 1802, the tunnel fell into disrepair. Between 1840 and 1845, the Delius and von Ammon families , the owners of the monastery and the lake at the time, had a parallel tunnel ( Delius tunnel ), about 5 m deeper and 1060 m long, driven , whereby the Fulbert tunnel was partly with the debris was moved. The area of ​​the lake decreased by 48 hectares due to the lowering of the water level .

Today nothing can be seen of the Fulbert tunnel for days. The original mouth hole was south of today's mouth hole (Delius) in the orchard. Small parts of the old Fulbert tunnel are still accessible above the current one.

Individual evidence

  1. Klaus Grewe: The Fulbert tunnel on the Laacher See. An engineering achievement of the high Middle Ages. Magazine Arch. Mittelalter 7, 1979, 107-142.
  2. Gerd Otto: The Fulbert tunnel, an engineering achievement of the high Middle Ages? In: Local research in the Eifel. 2006, archived from the original on August 1, 2012 ; accessed on April 21, 2016 .
  3. Hubertus Ritz village: Roman aqueducts in the Middle Rhine . Ed .: Archaeological Monument Preservation Office Koblenz (=  Archeology on the Middle Rhine and Moselle . Volume 15 ). State Office for Monument Preservation, Koblenz 2005, ISBN 978-3-929645-09-5 .
  4. Guido Kaspari: The Fulbert tunnel on the Laacher See. In: Heimatjahrbuch 1995. Landkreis Ahrweiler, p. 66 f , accessed on April 4, 2016 .

literature

  • Klaus Grewe : The Fulbert tunnel on the Laacher See. An engineering achievement of the high Middle Ages. In: Zeitschr. Arch. Mittelalter 7, 1979, pp. 107-142.
  • Klaus Grewe: The Karlsgraben near Weißenburg i. B. and the Fulbert tunnel by Maria Laach. In: U. Lindgren (ed.): European technology in the Middle Ages 800–1400. Tradition and innovation. Berlin 1996; Pp. 111-115.
  • Klaus Grewe: The Fulbert tunnel on the Laacher See (= Rheinischer Verein für Denkmalpflege und Landschaftsschutz (Hrsg.): Rheinische Kunststätten. Heft 513). 1st edition. Neusser Druckerei und Verlag GmbH, Neuss 2009, ISBN 978-3-86526-042-0 .

Web links