Oglio
The Oglio (; Latin "Ollius", or "Olius"; Lombard "Òi"; Cremonese "Ùi") is a left-side tributary of the river Po in Lombardy, Italy. It is long. In the hierarchy of the Po's tributaries, with its of length, it occupies the 2nd place per length (after the river Adda), while it is the 4th per basin surface (after Tanaro, Adda and Ticino), and the 3rd per average discharge at the mouth (after Ticino and Adda). Overview. The Oglio is formed from the confluence of two mountain streams, the Narcanello branch from the Presena Glacier, in the Adamello group and the  Frigidolfo branch, in the Corno dei Tre Signori, part of the Stelvio National Park. The streams merge near Pezzo di Ponte di Legno, both the streams have an average discharge of . The Frigidolfo branch, before merging with Narcanello branch, receives the Arcanello branch, which have an average discharge of , which receives a minor branch originating from Lake Ercavallo. The Ogliolo stream, with an average discharge of and a length of (similar to the length of the main branch between the "Frigidolfo-Narcanello merge" at Ponte Di Legno and the "Oglio-Ogliolo merge" at Edolo) is sometimes considered as a "de  facto" fourth branch of the Oglio river. It flows in a southwest direction, through Valcamonica and enters into the Lake Iseo at Costa Volpino. It leaves Lake Iseo at Sarnico and, after traveling a zone of moraine deposits, it joins the Po river at Torredoglio, not far from Cesole and Scorzarolo, in the province of Mantua. Its drainage basin, which corresponds to the region of Valle Camonica, covers . It is part of the larger Po-Adige basin. The course of the river main branch. Camonica Valley section. The river in the Camonica Valley flows almost exclusively in the province of  Brescia, entering in the province of Bergamo only at , on the border between Artogne, Brescia and Rogno, Bergamo. The following is a list (incomplete) of the tributaries in the Camonica Valley: Lake Iseo section. At Costa Volpino, the Oglio river enters the Iseo lake with a mixed delta-estuary mouth. Po Valley section. The Oglio main branch leaves the lake at the provincial border between Sarnico, Bergamo and Paratico, Brescia and begins to follow (approximately) this provincial border. At the triple provincial border between Torre Pallavicina (Bergamo), Roccafranca (Brescia) and Soncino (Cremona) the Oglio begins to follow (approximately) the provincial  border between the Brescia-Cremona provincial border. The major tributaries in the Po valley are the following: At this triple provincial border the Oglio river begins following the Mantua-Cremona provincial border, which leaves at the triple municipal border between Acquanegra sul Chiese (Mantua), Calvatone (Cremona) and Bozzolo (Mantua) where the river enters entirely in the Mantua province. At the municipal border between Marcaria and Viadana , the Oglio river enters the Po river.