Lake Trasimeno, also known as Trasimene, is a lake in the province of Perugia, Umbria, Italy, near the border with Tuscany. The lake is located south of the Po River and north of the Tiber River, and it has a surface area of 128 km2 (49.4 sq mi), making it the fourth largest in Italy, slightly smaller than Lake Como. Only two minor streams enter the lake directly, and none exist. The lake’s water level varies greatly depending on rainfall and seasonal demands from towns, villages, and farms near the shore.
The image above was taken on August 6, 2022, and the lake’s emerald green color is most likely due to the presence of phytoplankton. Streaks in the water, especially in the west, indicate the presence of soil and sediments stirred up by winds. Dark waters in the lake’s southern reaches indicate the presence of submerged and floating macrophytes (aquatic plants) as well as algae.
Trasimeno is surrounded by hills on three sides and is prone to heavy storms caused by winds, particularly from the north and west. The lake contains three islets: Maggiore, Minore, and Polvese (the largest). Only two popular villages line the lake’s shores: Castiglione del Lago and Passignano Sul Trasimeno.
It is the worst drought in 70 years in Italy, affecting drinking water supplies, hydroelectric power, and agricultural production. The main causes of drought in the Umbrian region are high temperatures, hot winds, and a lack of rainfall, which caused Lake Trasimeno to drop 1.3 meters, reaching the limit of hydrometric zero in July 2022.
