Stammham power plant dams up the River Inn upstream of the Alz estuary and Mittlinger Bach. Due to the partial diversion into the Alz canal towards Holzfeld, the inflow from the Alz to the Salzach normally only lies at 10 m3/s. In the case of flood events, substantial amounts of gravel are deposited on the bed of the River Inn.
The bank opposite the estuary, which accommodates the railway line to Simbach, therefore had to be protected with breakwaters. Dredging work was necessary to retain the water level.
In the north, the valley is confined by the Dachleite, the old undercut slope of the Inn with almost vertical crumbling walls that rise to a height of over 100 metres. The high tertiary hills with the erosion fronts Dachlwand and Innhorn extend down to the river.
"Dachln" are jackdaws that nest in the cliffs.
Dams were necessary upstream near Holzhausen and to provide flood protection for Marktl. Braunau power plant, which is located downriver, dams the downstream water.
Stammham power plant, a flat construction building, has three machine units. The Kaplan turbines are directly coupled with umbrella-type alternators with an output of 10 MVA at power factor cos=0.8. Two transformers, each with 16 MVA, transform electricity from 6.3 to 110 kV in the switchyard. The power plant feeds into the Neuötting-Braunau line on the left bank of the Inn.