| Oglio | |
| Map: | Oglio.png |
| Map Size: | 250px |
| Subdivision Type1: | country |
| Subdivision Name1: | Italy |
| Subdivision Type2: | region |
| Subdivision Name2: | Lombardy |
| Subdivision Type3: | provinces |
| Subdivision Name3: | Brescia, Bergamo, Cremona, Mantua |
| Source1: | Valle delle Messi, as Frigidolfo branch |
| Source1 Location: | near Punta Valmalza, Sobretta-Gavia Group, Ortler Alps, Lombardy |
| Source1 Elevation: | 3035m (9,957feet) |
| Source1 Coordinates: | 46.3421°N 10.451°W |
| Source2: | Lake Ercavallo, Valle di Viso, as Arcanello branch |
| Source2 Location: | at the slopes of Cima di Caione, Ortler Alps, Lombardy |
| Source2 Elevation: | 2621m (8,599feet) |
| Source2 Coordinates: | 46.3392°N 10.5265°W |
| Source3: | Lake Pisgana, as Narcanello branch |
| Source3 Location: | Narcanello Valley, near Vedretta di Pisgana, Presena glacier, Adamello-Presanella Alps, Lombardy |
| Source3 Elevation: | 2500m (8,200feet) |
| Source3 Coordinates: | 46.2061°N 10.5303°W |
| Source4: | Ogliolo branch |
| Source4 Location: | Corteno Valley, on the provincial border between Corteno Golgi, province of Brescia and Aprica, province of Sondrio, Lombardy, near Zappello dell'Asino |
| Source4 Elevation: | 1172m (3,845feet) |
| Source4 Coordinates: | 46.1478°N 10.1651°W |
| Source Confluence: | confluence of Frigidolfo and Narcanello branches |
| Source Confluence Location: | Ponte di Legno, province of Brescia, Lombardy |
| Source Confluence Elevation: | 1253m (4,111feet) |
| Source Confluence Coordinates: | 46.2591°N 10.508°W |
| Mouth: | Po |
| Mouth Location: | at the municipal border between Marcaria and Viadana, province of Mantua, Lombardy |
| Mouth Coordinates: | 45.0444°N 10.6603°W |
| Length: | 280km (170miles) |
| Discharge1 Avg: | 137m3/s |
| Basin Size: | 6649km2 |
The Oglio (pronounced as /it/; Latin: Ollius or Latin: Olius; Òi, label=[[Cremunés dialect|Cremonese]]|Ùi) is a left-side tributary of the river Po in Lombardy, Italy. It is 280km (170miles) long.In the hierarchy of the Po's tributaries, with its 280km (170miles) 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).
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 1.5m3/s.The Frigidolfo branch, before merging with Narcanello branch, receives the Arcanello branch, which have an average discharge of 0.5m3/s, which receives a minor branch originating from Lake Ercavallo.The Ogliolo stream, with an average discharge of 2.5m3/s and a length of 20km (10miles) (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 6649km2. It is part of the larger Po-Adige basin.
The river in the Camonica Valley flows almost exclusively in the province of Brescia, entering in the province of Bergamo only at 45.8606°N 10.1489°W, on the border between Artogne, Brescia and Rogno, Bergamo.
The following is a list (incomplete) of the tributaries in the Camonica Valley:
At Costa Volpino, the Oglio river enters the Iseo lake with a mixed delta-estuary mouth.
The Oglio main branch leaves the lake at the provincial border between Sarnico, Bergamo and Paratico, Brescia 45.6657°N 9.9567°W and begins to follow (approximately) this provincial border.At the triple provincial border between Torre Pallavicina (Bergamo), Roccafranca (Brescia) and Soncino (Cremona) 45.4279°N 9.8854°W 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) 45.1325°N 10.4922°W where the river enters entirely in the Mantua province.
At the municipal border between Marcaria and Viadana 45.0444°N 10.6603°W, the Oglio river enters the Po river.