Po (river)

The Po (poʊ , ˈpɔ) is the longest river in Italy. It flows eastward across northern Italy starting from the Cottian Alps. The river's length is either or , if the Maira, a right bank tributary, is included. The headwaters of the Po are a spring seeping from a stony hillside at Pian del Re, a flat place at the head of the Val Po under the northwest face of Monviso. The Po then extends along the 45th parallel north before ending at a delta projecting into the Adriatic Sea near Venice. It is characterized by its large discharge (several rivers over 1,000 km have a discharge inferior or equal to the Po). It is, with the Rhône and Nile, one of the three Mediterranean rivers with the largest water discharge. As a result of its characteristics, the river is subject to heavy flooding. Consequently, over half its length is controlled with embankments. The river flows through many important Italian cities, including Turin, Piacenza, Cremona and Ferrara. It is connected to Milan through a net of channels called navigli, which Leonardo da Vinci helped design. Near the end of its course, it creates a wide delta (with hundreds of small channels and five main ones, called Po di Maestra, Po della Pila, Po delle Tolle, Po di Gnocca and Po di Goro) at the southern part of which is Comacchio, an area famous for eels. The Po Valley was the territory of Roman Cisalpine Gaul, divided into Cispadane Gaul (south of the Po) and Transpadane Gaul (north of the Po). The Po has a drainage area of 74,000 km2 in all, 70,000 of those being in Italy, of which 41,000 is in montane environments and 29,000 on the plain. The slope of the Po's river valley decreases from 0.35% in the west to 0.14% in the east, a low gradient. Along its path lie 450 standing lakes. Almost all of the rest of the non-Italy basin is in Switzerland, primarily in the canton of Ticino, which is essentially drained by the Ticino river rising in the Gotthard Area, and includes Lake Maggiore and Lake Lugano. A small part of Grisons canton drains to the Po, partly via the Ticino.