[2] It drains the western side of the Southern Alps / Kā Tiritiri o te Moana and heads in a northerly direction for 60 kilometres (37 mi), flowing into Jackson Bay / Okahu.

[4] Access to the glaciers, forests and flats of the upper reaches of the valley is restricted by Ten Hour Gorge.

Glacial silt in the river imparts an opaque green to greyish coloration to the water.

The majority of the land in the area is publicly owned and administered by the Department of Conservation.

[5] Owing to the high rainfall on the western side of the Southern Alps, the river level can rapidly rise.