Lake Trasimeno is the largest lake in central Italy, with an area of about 130 square kilometers, with a shallow (average 4.3 m, maximum 6 m) so that the Trasimeno is one of the lakes laminar. Lake Trasimeno is part of the province of Perugia, in the Umbria region.
The nature surrounding Lake Trasimeno looks like an amphitheater hill that frames its surface; the west coast extends in a flat area open to Tuscany in the Val di Chiana and the north-west of the territory of the Trasimeno area marks the border between the provinces of Perugia and the provinces of Siena and Arezzo.
The origin of the lake basin is linked to tectonic phenomena accompanying the final stages of the Apennine orogeny. Five million years ago, the lake Trasimeno was simply a gulf of the Tyrrhenian Sea, then, with the lowering of the sea level, the area was occupied by a body of freshwater in the last 500,000 years did detect changes in the level of 'water very high, with evidence of dieback almost the whole surface of the lake and periods of heavy rainfall with a high intake of sand into the lake.
The area was inhabited since prehistoric times, as evidenced by the findings today preserved in the National Archaeological Museum of Umbria. In 217 B.C. on the shores of the lake took place the Battle of Lake Trasimeno, which saw the Carthaginian forces of Hannibal defeated the Roman legions of the consul Gaius Flaminius. Subsequently, at the time of the Emperor Claudius, to overcome the problem of frequent flooding of Lake Trasimeno, the Romans built the first artificial outlet connected to the Tiber.
In 1422 Braccio da Montone, lord of Perugia, did make a new emissary, for a total length of about 1 km and developed almost entirely in the gallery. This work, however, was not decisive of the problems to the point that even the famous Leonardo da Vinci studied an ingenious hydraulic system, never put in place to regulate the flows in excess of the Trasimeno and Lake Chiusi, which also included the involvement of the Tiber and Arno. In the second half of the sixteenth century, Pope Sixtus V decided to divert the only natural tributaries of Lake Trasimeno, the Rigo Maggiore and the Tresa, towards the lake of Chiusi. Between the eighteenth and nineteenth century there was an attempt further reduction in the catchment area (it was even talk of drainage) but were later operated interventions.
After years of hard battles with the state property and speculators, between 1896 and 1898, the Consortium of Reclamation chaired by Guido Pompilj managed to build a new emissary, parallel to that of the fifteenth century,
Averted so the artificial drying (for which had already been issued granting real) and solved the problem of floods and consequent malaria, including the forties and fifties of the XX century, due to the intensive use of the lowering of the threshold the new emissary in favor of the powerful landowners, had to deal with a water crisis: the Trasimeno even ran a serious risk of drying up, with a maximum depth which decreased to 2.93 meters at the end of the fifties.
In 1952, they were then re-introduced the natural tributaries Rio Maggiore and Tresa, rerouted in the sixteenth century, and the recovery took place from 1958 Recently, the lake Trasimeno has entered a new water crisis, perhaps greater than that of the fifties: his maximum depth at present is 4.30 meters, but between 2007 and 2008 fell by 78 cm. Due to heavy rainfall in October 2011 Tues 2012, the lake level has increased significantly (over a meter) and reached less than 40 cm. compared to the hydrometric zero place to 257.33 m asl The rainfall in spring 2013 allowed the Umbrian basin to reach minus 29 cm., A record that, according to the engineers of the province of Perugia has not been seen for at least twenty years. In February 2014, the Trasimeno reached again after 25 years, the hydrometric zero. Merit also of the maintenance work and cleaning of canals and ditches that run on adduction.
Since 2006, the lake Trasimeno is part of the international "Living Lakes".
The hills around the lake are the production area of a well-known wine called Colli del Trasimeno.
FAUNA OF TRASIMENO
In addition to typical mammals in the area like the fox, porcupine and wild boar, is a tiny mammals: shrews. Birds: There are of course the seasonal variations of avian fauna due to migration. We find, however, great crested grebes, cormorants, coots, Pochard, Wigeon, peacocks, pheasants and mallards and of course the seagulls.
Visiting the Oasis Valley near San Savino in the area where the more extensive the extraordinary environment of the reeds to whom we owe the wealth of species that can be observed. Lake Trasimeno is one of the most important wetlands in Europe and privileged laboratory to experiment with forms of sustainable development that can prevent and reduce the current environmental crisis. One of the indicators of quality is the passage of migratory routes of hundreds of species of birds, many stop to nest, the other in winter, still others just to stock up on food during the journey, so that each season of the year makes several observations and interesting
It has a rich fish fauna of this lake basin: the species present are 18, but only 5 of them are indigenous species have not been placed by man. These species include pike, carp (common, mirror, herbivorous), tench, chub, crucian carp (weeds), bleak, rudd, perch, eels, perch trout, Gambusia, ghiozzetti cenerini, ghiozzetti lagoon. Among the extinct species is reminiscent of the laschetta or roach (Rutilus rubilio), once abundant in the lake and died in the fifties for the competition conducted by the translocated roach, provenance Valley.
An area monitoring conducted between 2002 and 2005 made it possible to conduct a census 7 species of amphibians Triturus carnifex, Triturus vulgaris meridionalis, Hyla intermedia, Bufo bufo, Rana bergeri, hispanica Rana, Rana Dalmatian and 9 reptile species: Testudo hermanni , Trachemys scripta, Lacerta bilineata, Podarcis muralis, Podarcis sicula, Hierophis viridiflavus, Zamenis longissimus, Natrix Natrix natrix and tessellated.
ISLANDS OF TRASIMENO
In Lake Trasimeno are three islands namely, in order of magnitude, the Polvese, the Major and
The island Polvese is located in the south-east and is the largest island of the three (69.60 hectares). Since 1995, the Province of Perugia, owner since 1973, the park was declared a scientific-educational and there conducts scientific research, testing and teaching environment. In the eastern and southern Africa is a vast wetland which gives shelter to various species of birds and amphibians.
The island Maggiore is the only inhabited island in a stable manner, in fact, the island has 18 inhabitants (Istat, 2011) and has an area of 24 hectares, enclosed in a perimeter of 2 km. The island is connected to the mainland by a ferry service to the countries of Tuoro sul Trasimeno, Passignano and Castiglione del Lago. A dense network of trails covers the whole island, unraveling through a grove of olive trees, holm oak, pine , cypress, poplar and other Mediterranean varieties.
The island Minor rises to about 20 m from the surface of the lake (258 m), has the form of a comma with dimensions of about 450 x 260 m and a total area of 0.05 km ². The island is covered by dense forest vegetation, including pines and oaks, which as a refuge for a large colony of cormorants.