Energy generation, protection against flooding and securing the Danube water level were the reasons for creating a large reservoir – the Forggensee. The lake basin filled with water for the first time in 1954.

With a length of up to 12 km, a width of 3 km and a water surface area of almost 17 square kilometers, one of Bavaria’s largest reservoirs was created. It reaches its normal water level in mid-June. Municipal areas of Füssen, Halblech, Rieden, Roßhaupten and Schwangau sank into the lake. At the power station at barrage 1, near Roßhaupten, an information center shows details of the expansion and technology.