Trübtensee July 2013. Switzerland Ludvik Daněk(c)daluphoto.ch 2013. Trübtensee or Triebtenseewli is a lake in the municipality of Guttannen, Bernese Oberland, Switzerland. The reservoir's surface area is 0.1 km². Its dam was completed in the 1950s and holds a volume of 1.1 mio m³.