Its hydrology is particular: there are neither tributaries nor emissaries. The lake is fed by a surface spring, some underground springs and rainwater. The basin of the lake, elliptical in shape and about two meters deep at most, is a sinkhole, i.e. a surface cavity characteristic of karst terrains produced by the action of water on the limestone.

The origin of Lake Soprano is rather controversial but two postcards depicting soldiers on boats on the lake sent in July 1907 trace its formation back to at least the early years of the century.
The reserve, established in 2000 and managed by the regional province of Caltanissetta, was created to protect the homonymous lake. The lake mirror is set on marly limestones (called Trubi) which mark the end of the Messinian period and the return to open sea conditions. Its origin, dating back to the beginning of the last century, is due to the sinking phenomena of the superficial rocky banks which occurred following the processes of solution of the underlying evaporite deposits (sinkhole).
In the past, man lived together on the banks of this area by exploiting the waters: some residue of the ancient custom of water mills is in fact left.

The proximity to the town has determined, on the one hand, the high impact of man on the lake, and on the other the interest in its protection. The hydrogeological and landscape constraints as well as the prohibition of hunting fall on the lake.
For its vegetational emergencies, the Italian Botanical Society has included the lake among the biotopes of significant vegetational interest and worthy of conservation and by the Civil Engineers in the list of public waters.
In 1978, however, the municipal administration decided to reclaim it. Only after years of effort have environmental associations, including the WWF, managed to prevent its destruction.
In 1985 the WWF section of Caltanissetta presented a “Management proposal of the Serradifalco lake Soprano oriented nature reserve” accompanied by a very detailed study of the biotope and various practical proposals. An expanded edition was published in January 1988.

Among the interventions suggested to safeguard the lake are the restoration of the landscape, the maintenance of the water level and the restoration of the ecosystem.
Today the lake is still in danger of disappearing as the sewers have been rightly eliminated but nothing has been done to supply this lake basin with the water necessary for its maintenance.
The establishment of the reserve will allow for the protection of the lake and its public use through huts and nature trails with a positive effect on the local economy.

The most numerous animals are the Coot (Fulica atra) and the Pochard (Aythya ferina) which have been nesting there for years.
Other typical birds of the lacustrine environments and present at Lake Soprano are the Teal (Anas crecca), the Moorhen (Gallinula chloropus), the Little Grebe (Tachybaptus ruficollis) and the rarer Little Grebe (Podiceps nigricollis).
The muddy areas are the preferred habitat of waders such as the Pantana (Tringa nebularia), the Black Godwit (Limosa limosa), the Common Leg (Chalidris minuta), the sandpiper (Tryngites spp.).
The reeds house the nests of various birds: the reed warbler (Acrocephalus scirpaceus), the nightingale (Cettia cetti), the little bittern (Ixobrychus minutus), the reed warbler (Acrocephalus arundinaceus) and the water rail (Rallus aquaticus), so called because its distinctive grunt-like call.

Today it is more possible, thanks to the ban on hunting, to observe Gray herons (Ardea cinerea), Night herons (Nycticorax nycticorax), Pintails (Anas acuta), Shelducks (Tadorna tadorna), Ferruginous ducks (Aythya nyroca), Garganeys (Anas querquedula) and Shovelers (Spatula clypeata).
Occasionally there are also typically marine species such as gulls or rare species such as spoonbill (Platalea leucorodia).
The area is home to the few species of mammals commonly found in the surrounding countryside such as the wood mouse, the dwarf bat (Pipistrellus pipistrellus), the weasel (Mustela nivalis), the wild rabbit (Oryctolagus cuniculus), the Apennine hare (Lepus corsicanus) and the Fox (Vulpes vulpes).

In the waters of the lake swims the collared snake (Natrix natrix) of a uniform dark color with a white “collar” near the head. It mainly nourishes of green frogs (Rana esculenta s.l.) and toads (Bufo bufo). If disturbed it can whistle and strike with its mouth closed, it rarely bites. Sometimes she can play dead by rolling onto her back with her tongue hanging out. At night you can easily see the gecko or wall tarantula (Tarentola mauritanica) which feeds on insects. He has sticky pads on his fingers.
The pond turtle (Emys orbicularis) lives in the water, a reptile which, until recently, was believed to be no longer present.
Along the banks it is possible to see the Mole cricket (Gryllotalpa gryllotalpa), an orthoptera with highly developed front legs and adapted to dig the underground tunnels where it takes refuge.

The waters of the lake are also home to a myriad of microscopic beings: it is one of the least known aspects but no less fascinating and noteworthy.

The lake is home to various fish species, including perch (Perca pluviatilis) and carp (cyprinus carpio), together with a rich plankton where daphnia (Daphnia ssp.) prevail, also known as “water fleas” due to their movement in jumps.
Other species related to the aquatic environment also live in the reserve such as green frogs and the common toad (Bufo bufo), among the amphibians, the grass snake (Natrix natrix) and the marsh turtle (Emys orbicularis), among the reptiles.
For reptiles, the common gecko (Tarentola mauritanica) is also reported in the reserve.

The hosted mammals are the fox (Vulpes vulpes), the weasel (Mustela nivalis), the wild rabbit (Oryctolagus cuniculus), the Apennine hare (Lepus corsicanus), the wood mouse (Apodemus sylvaticus) and the dwarf bat (Pipistrellus pistrellus).

In the lake lives the spongy duckweed (Lemna gibba), a hydrophyte that floats in the water with the leaves on the surface and the free roots immersed, this, depending on the period, can cover from 20 to 100% of the lake surface .
Around the lake there is a more external band colonized by the marsh reed (Phragmites australis), where various species of birds nest, and a greater herringbone band (Thypha latifolia), a herbaceous plant up to three meters high which, between June and July, two tapered inflorescences, superimposed on each other.

In summer there is also the presence of other plant species such as poleggio mint (Mentha pulegium), hairy heliotrope (Heliotropium supinum) and ovate brignolo (Crypsis schoenoides).
The flora of the lake is continuously damaged and altered by human intervention. The prevailing plant association is the Mediterranean Scirpo-fragmiteto.

The most widespread species is the common reed (Phragmites australis) which forms the outermost belt. It is a common plant in marshy environments. Its rhizome has medicinal properties while the stem can be used for packaging and mats. It has the ability to filter and purify water. Form of rather dense spots: an excellent refuge for the nesting of various species.
This is followed by the herringbone or Buda band (Typha latifolia) whose brown, cylindrical and compact female spike is characteristic and is often used for decorative purposes.
The spongy duckweed (Lemna gibba) floats on the lake and can cover from 20 to 100% of the lake surface.
In summer, the presence of the Glino-heliotropieto is noted, another plant association, which is characterized by the hairy heliotrope (Heliotropium supinum), a Boraginaceae with white flowers, by the ovate brignolo (Crypsis schoenoides) and by the poleggio mint (Mentha pulegium). . It is a typical association of Sicilian artificial basins.