Even though the lake has a regulating effect, it is subject to water level variations that may exceed 3 m and reflect in the discharge at the outflow. At a short distance from the Petrohué locality, the river flows through the Petrohué Waterfalls.
The lake's influence is regulatory, but it is subject to fluctuations in water level that may exceed 3 meters and affect the outflow.  The river flows through the Petrohué Waterfalls close to the Petrohué locality.