Alb Basin, reservoir in St. Blasien, Dachsberg, Germany

The Alb Basin (Albstausee) is a storage reservoir in the Alb valley near St. Blasien, held by a 28-metre-high gravity dam. It lies at about 737 metres above sea level, mostly in St. Blasien but with the dam wall in Dachsberg. The Landesstraße 154 runs along its eastern shore for about 1.4 kilometres.

The Alb Basin is one of two side arms in the pumped storage network of Schluchseewerk AG, based in Laufenburg, linking the Schluchsee and the Rhine near Waldshut. Its 28-metre gravity dam lies entirely in the municipality of Dachsberg, while most of the water surface belongs to St. Blasien. During a reservoir clean-out, the sediments were not taken to landfill but washed into a bird island.

The reservoir takes its name from the River Alb, whose valley it occupies; the German name Albstausee is used alongside Albbecken. The Schluchseewerk network links it with the Mettma Reservoir as one of two side arms around the Schwarzabruck Reservoir. The Landesstraße 154, the Albtalstraße, runs about 1.4 km along the eastern shore on its way from Albbruck to St. Blasien.

The L154 (Albtalstraße) runs about 1.4 km along the eastern shore before reaching St. Blasien. The dam wall stands on Dachsberg municipal territory, while most of the water lies in St. Blasien. The southern end of the reservoir borders St. Blasien's trading estate.

Sediments that settle at the bottom of the lake are not removed but instead spread onto a small island in the middle of the water, creating habitat for birds and wildlife. This approach shows how the reservoir's operation works with nature rather than against it.