Three inlets (Lido, Malamocco and Chioggia), 10 to 15 metres deep and 450 to 900 metres wide, connect the Lagoon and the northern Adriatic Sea. Average tidal excursion is between 80 centimetres and 30 centimetres (including spring and neap tide conditions) and water exchanges through the inlets demarcate three large-scale circulation patterns (north, central and southern Lagoon). Open waters and shallows, including the natural creeks and dug channels.