This blue, irregularly-shaped lake in the province of Terni has a surface area of 1.5 sq km and a perimeter of 13 km. It lies at a height of 368 m, surrounded by green hills. Its main tributary is the river called the Rio Ruscello, which collects most of the water that falls into the valley. The lake (called Velinus by the Romans) has its origins in the alluvial barrier of the River Velino. The floor of the lake was partly filled by the accretion of detritus but has now been largely excavated in order to increase the volume of water in the basin for hydro-electric purposes.
