Another name for the Buller River is Kawatiri (meaning deep and swift). It flows for 169km and finishes at the Tasman Sea near Westport. Much of the Buller River's catchment area is mountainous and thickly covered in native bush. For most of its length the river flows in steep-sided gorges with many rapids.Perhaps you're wondering where the name Buller came from? It was named after Charles Buller. Buller was a Member of Parliament and director of the New Zealand Company (The New Zealand Company was a 19th-century English company that played a key role in the colonisation of New Zealand).