Grabenbach

The Grabenbach is a tributary of the Saalach. It is about 4 kilometres long. For the first 1,878 metres the river flows in an underground channel under the city of Bad Reichenhall. The deepest part of it flows 11 metres below the surface.The tunnel was built after plans of Erasmus Grasser from about 1524 to 1538. After the route has been determined in 1522, the construction was started in 1524 under the direction of master builder Fabian Zehentner and the supervision of the Salzmaier Hans Humbs. The tunnel was dug from north to south, towards the higher saline. Therefore, with progressing work one had to dug deeper and deeper; a gradient of 8.5 metres had to be compensated. During 1,975 metres length, the canal was walled 2 metres high and 2.5 metres wide, vaulted and then filled with soil again. In 1534, the well shaft was reached and in 1538 the construction work was finished.

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