The Reschensee (Italian Lago di Resia) is a reservoir that serves as the upper pool for the Glurns storage power station. The artificial lake is six kilometers long and at its widest about one kilometer wide has a storage volume of 120 million m³, which is used almost entirely as a storage volume and thus forms a so-called annual storage. The water from the reservoir is conducted via a twelve-kilometer-long pressure tunnel with a diameter of three meters, which also absorbs water derived from other Adige tributaries, on the left side of the valley to above the cavern power station, where it has a fall height of 586 meters and two Pelton turbines each Drives 52.5 MVA generators. The average annual generation of electrical energy is approximately 250 gigawatt hours.
In the immediate vicinity of the lake are next to the main town of the municipality, Graun, the villages of Reschen and St. Valentin on the Haide, as well as the hamlets of Kaschon and Spin.
Up to the lake congestion in 1950 there were three lakes on the Reschenpass: Lake Reschensee, Mittersee (also called Grauner See) and Haidersee, which still exists today. During the lake stowage, the entire village of Graun and a large part of the village of Reschen sank in the floods of the reservoir, a total of 163 houses and 523 hectares of fertile cultivated soil were flooded. Today only the church tower protruding from the Reschensee testifies to the sunken Alt-Graun. Wikipedia