Lago del Barbellino, Reservoir in the Bergamasque Alps, Valbondione, Italy

Lago del Barbellino is an artificial reservoir in the upper Seriana Valley, in the municipality of Valbondione, province of Bergamo. It lies at 1,862 m above sea level and is the largest artificial lake of the Bergamasque Orobie. The basin is 1 km long, 300 m wide and 60 m deep, holding 18.5 million m³ of water; its greenish tint comes from glacial silt carried by the Trobio stream. Steep shores and rocky mountainsides enclose the water.

The dam that holds the reservoir was built in the 1930s to collect water from several surrounding valleys and supply energy to the textile mills in the valley below. The construction flooded the original riverbed of the Serio and changed the shape of this part of the mountain for good.

The Barbellino lake sits in an area long used by mountain walkers from the Lombardy region, who follow trails that have been worn down by generations of hikers. The Curò Refuge near the shore is a stopping point where people share a meal or rest before continuing to the higher passes.

The walk to the lake begins in the village of Valbondione, where parking is available but fills quickly on summer weekends, so an early start is a good idea. The trail gains around 3,300 feet (1,000 m) in elevation, so solid footwear and enough water are needed before setting off.

Once a year the gates of the Barbellino dam are opened on purpose, releasing a waterfall called Cascate del Serio that ranks among the tallest in Europe. The event is announced in advance and draws people who travel specifically to watch the water fall from the valley floor.