Déviation de la Kander, River control structure in Bern, Switzerland.

The Kanderkorrektion is a river diversion at Einigen, where the Kander was led into Lake Thun through a tunnel cut into the Strättlighügel. The tunnel collapsed on 18 August 1714, and the river carved the Kanderschlucht gorge through loose moraine. The site today shows the canal mouth, the gorge and the Kanderdelta built up by sediment since 1913.

In 1711 Bern's council approved Samuel Bodmer's plan to cut through the Strättlig hill and divert the Kander into Lake Thun; work began in April 1711, and from 1712 Samuel Jenner led tunnel construction, interrupted by the Second Villmergen War. The roughly 300-metre tunnel was finished in December 1713, but on 16 July 1714 a section gave way under the water pressure, killing five people; on 18 August 1714 the tunnel collapsed entirely and the Kander gorge formed. It was Switzerland's first major river correction.

The name Kanderkorrektion covers both the 1711–1714 works and their unintended outcome: on 16 July 1714 a tunnel section gave way under the water pressure, killing five people, and on 18 August 1714 the tunnel collapsed entirely, leaving the Kanderschlucht gorge. The river now enters Lake Thun at Einigen, and its debris built the Kanderdelta, mined for gravel since 1913.

The breach site lies near Einigen at the end of the Schiffahrtskanal, where the intake structure of the 2007–2009 relief tunnel stands; the gorge itself is cut into loose moraine rock below Strättligen. The Kander delta at the lake mouth has been worked for gravel since 1913. Flood risk in Thun persists, so avoid the lower banks during high water.

The 1714 collapse killed five people and the tunnel gave way completely on 18 August 1714, leaving the Kanderschlucht gorge. The project's overseer, Samuel Bodmer, a baker and surveyor, later had to flee Thun after repeated flooding. The Kander delta at the lake mouth has been worked for gravel since 1913.