The Lago Ritom is a reservoir in Piora Valley (Val Piora ), a tributary of Leventina in the Swiss municipality of Quinto in Ticino.
The lake is glacial in origin and was extended in 1918 to the reservoir. This dam was built in 1950 extended to a height of 23 meters. Due to the porous subsoil at the top of this height is not fully usable. The reservoir is used for power production; the associated power plant belongs to the SBB, which thus generate traction power.
The lake is accessible via mountain trails, a driveway or on a very steep funicular railway (up 87.8 %). When the dam is also a guest.
In the original natural lake, the rare phenomenon of geogenic meromixis could be observed, ie the lack of seasonal mixing of the different water layers. This phenomenon disappeared after the construction of the dam. The neighboring Lake Cadagno is still an example of a lake without mixing and thus for biological research of interest.