The southern and final part of the river flows in a south-south-west direction following the eastern flank of Cordillera de Oncol.

[2] As a result of this, a large area of former pastures and cultivated fields around the lower course of Cruces River was permanently flooded.

[2] Coincident with the opening of the Valdivia Pulp Mill in 2004 there was a sharp decline of the black-necked swan population in the wetlands of the lower course of Cruces River.

[4][3] The event unleashed a large environmental conflict between citizens of Valdivia and nearby areas and Celulosa Arauco y Constitución, the owner of the pulp mill.

[5] Such events tend to happen in autumn and are expected to become more frequent in the future due to a trend of diminished rainfall.