The Rißbach comes from the northern part of the Karwendel mountains, where it gathers the water of smaller streams in the Ahornboden area. After crossing the border between Tirol and Bavaria, and immediately after the inlet of the Fermersbach, a 6960 m lug carries water to the hydro-electric power plant at Niedernach at the southeast end of the Walchensee. The power station has been in operation since 1951.