The « Syndicat Mixte d’Aménagement de l’Arve et de ses affluents » (SM3A) is a local authority situated in the Haute Savoie department, in the French Alps. It covers the whole Arve River catchment (2100 km2), which is fed by glaciers of the Mont Blanc mountain range, and flows down to the Rhone River in Geneva. The organisation has been created in 1995 to face the main societal challenges associated with river flow mitigation, in particular torrential floods, which in this region are highly impacted by the convey of water through glaciated systems. The authority runs key actions (i) to prevent local bed erosion (provoking infrastructure instabilities) and water pollution (induced by intensive industrial activities), and (ii) to ensure river quality and the preservation of aquatic systems.

SM3A runs several observatories on river, glacier and meteorological processes within the Arve Valley.