It drains the Mackenzie Basin and runs 209 kilometres (130 mi) south-east to enter the Pacific Ocean between Timaru and Oamaru on the east coast.

The middle of the river bed formed a traditional political boundary between Canterbury and Otago.

The Waitaki Hydro Scheme, which includes several large dams, is one of the largest hydroelectric projects in the nation.

Lake Pukaki was initially dammed at this stage to provide storage and flow control.

The stations are (commissioned/capacity/annual output): In 2001 a proposal for a new series of canals and dams was made by Meridian Energy for irrigation and electricity generation on the river.

[5] A more modest successor scheme, the North Bank tunnel looked likely to proceed, with water rights being granted in 2009,[6] but land access negotiations were suspended in January 2013 due to flat demand for electricity forecast for the next five years.