The Nature Reserve involves two river stretches: the first stretch is situated upstream Predosa and the second stretch lies between Retorto and Casalcermelli.
Willows and poplars cover the areas surrounding the riverbed and the degrading banks of the stream. Some uncontaminated sections of riparian woodlands house foxes, badgers, beech martens, weasels, hares, roe deer, and Apennine wild boars. Besides the nesting Night Herons and Little Egrets, also Gray Herons, Moorhens, Terns, and Little-ringed Plovers live here. In the riverbed it is still possible to find some golden specks and, sometimes, the gold diggers.