The Finstertal dam in Austria is a 150 m high rockfill dam with an asphaltic concrete core of 96m, located at an altitude of 2325 m above sea-level. The special topography of the dam site made it sit above the deepest foundation of the downstream shoulder. The dam was built in the years of 1977 to 1980. Difficult climatic conditions, at an altitude of over 2300 m, meant that construction work was only possible on around 100 days in the year. It is an early representative in the development of this type of dam, featuring
an inclined thin core (surface of 37 000 m², thickness decreasing with height from 70 to 50 cm);
a generous monitoring system with several innovations, justified by the pioneering role of this dam; it covers the deformation behaviour of the entire dam body with particular focus on the core and the adjacent central zone, and is complemented by precise sectional seepage control;
The Finstertal dam has operated without a hitch over 28 years. Surface deformations, with maximum settlements of 38 cm and maximum horizontal deflections of 19 cm, are of a magnitude that would hardly have been considered possible with earlier rockfill dams of such a height. Total seepage water losses through the 37,000 m2 core membrane surface were only 9 l/s on first filling, and declined to 1.5 l/s by the end of 2008.
The project is owned by Tiroler Wasserkraft AG (TIWAG), Tyrolean Hydro-Electric Power Company.