The Baslerweiher is actually created artificially. In the 19th century, the Kleinsee was created as a drinking water reservoir for the city of Basel, 20 kilometers away (and financed by the city, hence the name). It was not until 2008 that the Baslerweiher became the property of the Canton of Solothurn and immediately became the largest lake in the canton.
The Baslerweier is an artificial lake that served as a drinking water supply for Basel for 70 years from 1870. Today it belongs to the canton of Solothurn and is a nature reserve. A true idyll!