Tivoli has a close relationship with the Aniene River, which flows along the northeastern side of the modern city. With its many smaller streams, the river is a key natural feature that gives the area its unique charm and character.
Originating in the Simbruini Mountains, on the border between Lazio and Abruzzo, the river—once known as Parensio—owes its name to the legendary disappearance of the Etruscan king Anio, who drowned in its waters while trying to cross it during a flood, desperately chasing Cethegus, the man who had kidnapped his daughter.
Since its origins, the city of Tivoli has been closely tied to the Aniene River, which undoubtedly influenced its earliest settlement patterns. Throughout its history, however, the river has also posed a significant threat due to sudden and violent floods that often damaged homes and roads built along its soft, sediment-rich banks. The most dramatic floods on record include the one in 105 AD—mentioned by Pliny the Younger—and the last major one in 1826, which finally led to a lasting solution to the problem.
Thanks to the intervention of Pope Gregory XVI and the Sacred Congregation of Waters of Rome (led by Cardinal Rivarola as Prefect and Monsignor Massimo as Secretary), a major river regulation project was launched in 1835, based on a design by architect Clemente Folchi. The original course of the river was diverted through the construction of the impressive Gregorian Tunnels—two galleries that, by cutting through the rock… Mount Catillo for nearly 300 m, they drop through the 105-meter-high artificial waterfall, visible from Villa Gregoriana, the amount of water essential to the reunion with the old natural basin, into which until that date it reached through the chasms below the acropolis.
As a continuation of the work on the river, work was completed in 1929 on the construction of the St. John Hydroelectric Basin to regularize the flow of water to the Acquoria hydroelectric power plant (in operation since 1880) through penstocks.
The Basin was built by the Aniene Hydroelectric Consortium (C.I.A.).
Today the Aniene, after passing through the Apennine ranges, reaches Tivoli and, having passed through Gregorian tunnels, makes the thunderous leap of the Great Falls continuing its course into the caves of Neptune and the Sibyl.
After the jump, the river changes character, continuing its course with slow meanders into the Roman countryside where it joins the Tiber.
The abundance and continuity of the water that feeds it make the Aniene a river of good flow, which was in fact used since ancient times to supply the Roman Aqueducts in the Tiburtine area, and later as a resource for local industrial production and power generation.
From a naturalistic point of view, it is observed how plant species from different environments come into contact on the banks of the artificial reservoir.
Some of them, present in a few specimens, harken back to more natural riparian vegetation in the more upstream reaches of the river, such as black alder(Alnus glutinosa L. Gaertner), willow(Salix alba L.) and poplars(Populus nigra L. and Populus albaL.) typical of areas further up the riverbed.
At present, the basin provides an ideal habitat for various animal species, and in particular for the avifauna of freshwater environments, where a band of Phragmites reeds, a frequent formation in marshy and riparian areas, develops in stretches where the water slows its course by facing level fluctuations.
Numerous species of waterfowl are observed along the reedbed, including the mallard(Anas platyrhynchos), a sparse-looking surface anatid, which in the male in nuptial livery has an iridescent green head and upper neck, with a white collar, purple-brown back and blue-violet wing mirror edged with white.
Frequent sightings of the cormorant(Phalacrocorax carbo) during deep fishing dives, or resting with wings half-opened intent on drying the permeable blackish-colored feathers.
Encounters with the grey heron(Ardea cinerea), with its large wingspan of up to 170 cm and “S-shaped” bent neck during characteristic flight from slow, deep wing strokes, are not uncommon.
Along the river since ancient times there has been fish farming, one of the most important products on which the Roman diet was based.
Numerous vivarium (breeding places for freshwater fish) have been identified in the Roman villas that populate the Tiburtine territory, first of all the one still preserved and visitable inside the Villa of Manlius Vopisco in the park of Villa Gregoriana, referable to the 2nd century A.D., where one can see the tanks, fed by a direct aqueduct and characterized by the presence of holes on which amphorae are set for the nesting and reproduction of fish.
There were also many fishponds in the villas of wealthy patricians to have fresh fish available to enrich their tables, such as those located in the Emperor Hadrian’s villa.
The Agronomist Columella, in the 1st century A.D., recounts that the Romans’ favorite fish were bream, trout, sea bass, sole and also moray eels and eels; the Fario trout (salmo trutta forma fario), which has also populated the fishponds of the Villa d’Este garden since the Renaissance, represents a characteristic fish for the Tiburtine farms and gastronomy.
The trout is an indication of good water quality in fact it only lives in clean water with good oxygenation.
At local restaurants it is possible to find numerous recipes with Aniene trout.There is also a fish farm in the area that, referring to the ancient fishponds and using an old canal, is crossed by the water of the Aniene by natural fall.The trout is an indication of the good quality of the water in fact it lives only in clean water with good oxygenation.
Easily find all the tourist sites to visit in Tivoli
