This lake in the Apennine mountain range was formed by damming the Sangro River to generate hydroelectric power. Surrounded by riparian forests of willows (Salix spp.) and white poplars (Populus alba), the Site is especially important for nationally endangered migratory birds Aythya ferina and Anas crecca. The reservoir is a vital water resource for deer, wolves and the Marsican brown bear, a critically endangered subspecies of the Eurasian brown bear (Ursus arctos arctos). Fluctuations in water levels were formerly a threat to the Site, but they are now strictly regulated and this has led to the appearance of submerged vegetation and contributed to the return of the otter (Lutra lutra). In 2021 the Site boundary was extended to the west and the total area calculated more accurately. During the summer months, the lake is a popular destination for picnics, outings and nature observation.