Lake Maggiore is located at about 193 m asl, its surface is about 212 km ² of which about 80% are located in Italian territory and the remaining 20% in Switzerland. Has a perimeter of 170 km and a length of 54 km (the largest of the Italian lakes), the maximum width of 10 km and the average of 3.9 km. The volume of water content amounts to 37.5 billion cubic meters of water with a theoretical time of replacement of approximately 4 years . The catchment area is very wide, approximately 6,599 km ² divided almost equally between Italy and Switzerland (the ratio between the surface of the lake basin and that is equal to 31.1). The maximum altitude of the basin is imbifero Dufourspitze in the Monte Rosa massif (4633 m) is the average instead of 1270 m sl The basin is characterized by a thirty dams with a collection of about 600 million cubic meters of water, if released in a contemporary way to raise the lake level of about 2.5 m. The maximum depth is about 370m (in between cryptodepression Ghiffa Valtravaglia and Porto).