Trasimeno

Lake Trasimeno
Sunset on Lake Trasimeno
Location	Umbria, Italy
Coordinates	43°08′N 12°06′E / 43.133°N 12.100°E / 43.133; 12.100Coordinates: 43°08′N 12°06′E / 43.133°N 12.100°E / 43.133; 12.100
Type	endorheic
Basin countries	Italy
Surface area	128 km2 (49 sq mi)
Average depth	4–5 m (13–16 ft)
Max. depth	6 m (20 ft)
Surface elevation	258 m (846 ft)
Islands	3 (Isola Polvese, Isola Maggiore, Isola Minore)
Website	www.lagotrasimeno.net

Lake Trasimeno (Italian: Lago Trasimeno, Italian pronunciation: [ˌlaːɡo traziˈmɛːno]; Latin: Trasumennus; Etruscan Tarśmina), also referred to as Trasimene or Thrasimene in English, is a lake in the province of Perugia, in the Umbria region of Italy. The lake is south of the river Po and north of the nearby river Tiber, has a surface area of 128 km² (49.4 sq mi) and is the fourth for surface area in Italy. (It is slightly smaller than Lake Como.) Only two minor streams flow directly into the Lake and none flows out. The water level of the lake fluctuates significantly according to rainfall levels and the seasonal demands from the towns, villages and farms near the shore.

Trasimeno is shallow, muddy, and rich in fish, including pike, carp, and tench. During the last 10 years it has been 5 meters deep, on average. Lake Trasimeno is an endorheic body of water; it is an impounded lake that receives water but has no outlet. Other endorheic bodies of water include the Caspian Sea, Aral Sea, Utah's Great Salt Lake, and the Dead Sea. Evaporation can lead to a buildup of minerals in the water, resulting in saline conditions, making these lakes sensitive to pressures from pollution.

The shallow waters meant that malarial mosquitoes prospered. To combat malaria, some mosquito larvae-eating fish were imported from USA during the 1950s. These fish are widely scattered, and some live in the lakes near Trasimeno. Although billions of larvae are eaten, there are still many mosquitoes and other insects.

The lake's water quality is still very good, as a study by conservation group Italia Nostra showed in 2005. This is believed to be largely due to the small population and a lack of large farms in the area.