Abstract The Tauern-Kaprun power system is located on the north side of the Central Alps along the Kaprun River near Zell am See, the county of Salzburg, Austria (Fig. 1). The entire plant consists of 3 large reservoirs, 5 major dams, nearly 30 km of water tunnels, a total water head of 1254 m, and 2 power houses producing together 332,000 kw. The German war industry required the immediate construction of a large number of hydro-electric power plants in the Alpine region with the help of forced labor. By the end of the war only the large Limberg water tunnel of the Tauern-Kaprun system was completed. The building activity was resumed when the American European Relief Program (ERP) guaranteed the continuation of the project. The power system was designed and built and is operated by the government-owned Alpen-Elektro Werke A. G. The entire plant is located in the highly metamorphosed Central Zone of the Alps which is divided into a lower part (probably of Carboniferous age) and a younger upper part (probably of Triassic age). Both parts cover the granite gneiss core which is not exposed in this section of the Alps. The lower "cover," Untere Schieferhuelle, is composed of chlorite schists, dolomites, and some calc-mica schists and phyllites, the upper "cover," Obere Schieferhuelle, chiefly of calc-mica schists and calc phyllites. The most common type of rock in the area of the site is calc-mica schist of variable mica content of the Obere Schieferhuelle. The Salzach valley, the main east-west drainage