Spullersee, Reservoir in the Lechquellen Mountains near Dalaas, Austria

Spullersee is a mountain lake located near Dalaas at approximately 2000 meters elevation, surrounded by rocky cliffs and green meadows. The deep blue water reflects the sky and mountains, with a dam holding back the water for electricity generation.

The lake was dammed between 1919 and 1925 by the Austrian Federal Railways to support electrification of the Arlberg Railway. Since then it has served electricity generation while maintaining its natural appearance despite this industrial use.

The name Spullersee comes from the Spullerbach stream, which rises just north of the lake and feeds the Lech. The Ravensburger Hütte nearby was the scene of vandalism and drunkenness during the power plant's construction in the early 1920s, as recorded in accounts of the strikes for better working conditions.

The lake lies at 1,803 m in the Lechquellen Mountains, on the Rhine-Danube watershed; the Spullerbach, a source stream of the Lech, rises just north of it. The ÖBB runs an automatic weather and snow-measuring station at 1,850 m by the shore. The water is fished for trout in summer; ice cover makes fishing impossible between December and February.

The lake bed lies on the Rhine-Danube watershed: it once drained south into the Alfenz toward the Rhine, and today its banks are dammed on both the south and north sides. To increase inflow, a diversion was driven through the mountain from the Zürser See.