Costa lake
The lake takes its name from the road that runs along the southern slope of Mt. Calbarina, and is located in a hollow surrounded by woody hills: Mt. Ricco to the south, Mts. Piccolo and Calbarina to the north. A thick grove of reeds grows all around the lake, and many patches of willow and cypress grow on its shores.
Costa lake is a site of remarkable natural and ecological importance, and is Colli Euganei’s largest and best-known natural body of water. Thermal springs, clearly visible from the water surface, feed the lake; thermal water flows at a temperature of about 45°C, which means that the lake is never colder than 17°-18°C, even in the winter. In the spring, when rainfalls are abundant, water from the countryside upstream and from cold springs at higher elevation also flow into the lake. Peat, a substance forming from the remains of decomposing plants especially in lakes and bogs, abounds in the surrounding area, thus giving the soil a characteristic black colour, and showing that the lake used to be much larger, but gradually shrank over time.

Costa lake - Arquà Petrarca
(photo by: PR Colli Euganei)