Description
The origin of the biotope is complex and is obviously attributable to the action of the watercourses present. In this area, the flow of the T. Noce is greatly slowed down by the valley's poor slope, which facilitates the deposit of the materials transported by the water. As a result, the torrent flows, from the height of Denno Stazione, over its own alluvium, to which are added those of the tributary watercourses, first among which are the T. Lovernatico and the T. Sporeggio on the right bank and the T. Rinassico on the left bank. Obviously, in addition to carrying alluvium, these tributaries contribute significantly to the water supply in the Biotope, and in fact this valley floor is very rich in water. It is therefore easy to see how easily the terrain can be soaked or even invaded by water, and thus provide shelter for rich perifluvial hygrophilous vegetation.
However, the current configuration of the land is also due to human intervention. In 1922, in fact, the course of the Torrente Noce was artificially dammed with a small dam at the most strategic point for the success of the operation, i.e. at the beginning of the Rocchetta gorge, creating a small lake. As a consequence of this damming, the water level upstream rose, and the course of the Noce River widened into an elongated, shallow basin known as 'Lago della Rocchetta'. This situation, however, was not to be definitive, either because of the large alluvial contribution of the watercourses that were rapidly filling the basin, or because of the large contributions of inert materials that a few years ago were dumped in the peripheral areas of the reservoir, which by then had become marshes worthy of note even from a naturalistic point of view.
At present, therefore, the southern portion of the Biotope is characterised by the long residual 'lake-river' of the Torrente Noce, the confluences of its tributary streams and large areas of landfill material.
Naturalistic aspects
The most characteristic vegetation element in the protected area consists of strips of riparian woodland with willows (especially Salix alba) and alders(Alnus incana and Alnus glutinosa); they form strips that border the watercourse, sometimes very thin, but on the whole well-preserved. Abundant herbaceous and shrubby riparian vegetation gives these thickets a 'wild' appearance, making them difficult to cross and thus performing a valuable 'filter' function against disturbance. In the Rocchetta area, the presence of semi-stagnant water has favoured the development of waterreed (Phragmites australis), which forms dense reed thickets.
The favourable position at the bottom of the valley of the Biotope and its relative quietness, together with the presence of running water, makes it particularly hospitable to wildlife. Numerous species of fish, amphibians and reptiles find suitable microenvironments for survival and reproduction in the protected area. The list of bird species nesting here is very long, and includes uncommon water-related entities: the mallard (Anas platyrhynchos), the moorhen (Gallinula chloropus), the coot (Fulica atra), the kingfisher (Alcedo atthis), the dipper (Cinclus cinclus), the river warbler (Cettia cetti) and the green warbler (Acrocephalus scirpaceus). The Biotope's role as a resting, refuge and feeding area for birds during their migratory movements should also not be forgotten. Finally, it is worth mentioning, as proof of the good health of the area, the presence among the mammals of species that are very sensitive to human disturbance, such as the badger (Meles meles) and the deer (Cervus elaphus).