What is "schwaltenweiher"

The Schwaltenweiher is a reservoir lake in the Ostallgäu foothills of the Alps. It lies from the Allgäu Alps between the towns of Seeg and Rückholz. It was named after the Schwaltenmühle mill built beside it, which was in turn named after the Schwalt or Schwald family. It is now used for bathing and fishing.