Its main tributary is the Tūtaki River but it is also fed by water flowing off the Braeburn Range.

[2] The river is popular destination for kayaking and trout fishing.

[3][4][5] William Fox was the New Zealand Company agent in Nelson when he explored the Buller as far south as Murchison in February 1846, with Thomas Brunner and Charles Heaphy.

They renamed the lower section of the Tiraumea River,[6] after the English MP, Ross Donnelly Mangles, one of the company's directors.

About 75% of the catchment is in native forest, so that water quality is generally good, the only exception being nitrates.