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Geneva: water everywhere

Lake Leman, supplying 80% of water for Geneva citizens

Switzerland enjoys plentiful water, thanks to its many lakes, glaciers and subterranean aquifers. In Geneva, 80% of water used in the canton comes from Lake Geneva. The water table provides the remaining 20%.

Diagram shows Lake Geneva and position of the Genevan aquifer

Lake Leman   Geneva water table
Area and volume of water
582 km²
  Surface 30 km²
Average altitude 372 m   Thickness 60 m
Maximum depth 310 m   Depth between 25 and 70 m
Average renewal time 12 years   Storage coefficient 12%
Average flow in Geneva 248 m³/s   Usable water supply 16 millions de m³
Median amount collected by SIG 1.3 m³/s      

The Arve aquifer: naturally filtered groundwater

Subterranean groundwater represents a natural reservoir in which water circulates in the gaps between gravel. Comprising a surface area of around 30 km², the Arve water table is primarily fed by infiltration of Arve waters. Covered by a watertight layer of ground, this water is protected from pollutants and only needs gentle disinfection to guarantees its bacteriological quality, as it is carried through pipes. Rich in mineral salts, it is harder than the lake water.

Diagram shows cross-section of the river environment of the Avre and Rhone, indicating the permeable moraine, the freshwater molasse, and sediment.