The Maori name for the Clutha from its source to the sea was Mata-au, meaning “surface current”, a reference no doubt to the river's swirling eddies. The early whalers and settlers of South Otago called the river and the district the Molyneux, and the name survived well into the gold mining era. It has often been stated that Cook gave the name Molyneux to the river, but this is incorrect for he never saw it.
What he did name was Molyneux Harbour which was probably in the vicinity of Waikawa. The correct name is the Clutha, first suggested in 1846 when the Scottish emigrants were preparing to settle in Otago.
The river has the largest catchment in New Zealand (8,480 sq. miles), and is reputed to have the greatest volume of water. It is the largest river in the South Island, being 150 miles from the lakes to the sea and 210 miles from its headwaters to the sea.
Its catchment area is most diverse. On the far west the country is mainly mountainous with peaks up to nearly 10,000 ft and a varying rainfall from 35–150 in. Large intermontane basins, with the intervening ranges rising between 3,000 and 6,000 ft, occupy the centre, along with extensive river flats and terraces between 900 and 500 ft altitude. Rainfall is as low as 12 in. per year at Alexandra, Central Otago. On the eastern and southern catchment area the country is generally lower, with hills to 3,000 ft and with a more rolling and mature landscape. Rainfall is higher, varying from 30–50 in. Approximately 2,800 sq. miles of catchment are held by the Lakes Wakatipu, Wanaka, and Hawea, which total 240 sq. miles of water surface.
Major tributaries below the lakes include the following rivers; Shotover, Nevis, Arrow, Roaring Meg, Bannockburn, Cardrona, Lindis, Fraser, Manuherikia, Teviot, Pomahaka, Waitahuna. Towns situated alongside the Clutha River or on the lakes drained by it are; Queenstown, Wanaka, Cromwell, Alexandra, Roxburgh, and Balclutha.
Inchclutha, a fertile delta formed between the two branches of the Clutha River below Balclutha, is famed for its production of vegetables, dairy products, and meat. The Matau is a narrow deep channel, the Koau is a wide shallow channel, and they join together at the sea coast. Mining and dredging operations in the interior of the province have deposited large quantities of tailings in the river scheme. The Clutha and its tributaries were a rich source of gold. Gabriel Read discovered gold at the Tuapeka in 1861, but the greatest rush was in 1862 when Hartley and Reilly made their discovery at the Dunstan, a little below the junction of the Kawarau and the Clutha. Towards the close of the century the dredging boom began and in 1900 – the peak year – there were 187 dredges at work.
Eleven major floods and nine minor floods have occurred in the Clutha, the largest being in 1878 when the flow was estimated at 200,000 cusecs. In 1957 a flood of 107,000 cusecs affected 17,000 acres and cost New Zealand £650,000 in damages and loss in production. The river is well bridged and one punt still operates at Tuapeka Mouth. The deep entrenchment in gorges between Alexandra and Tuapeka Mouth permits no storage of flood waters. A £1,366,000 detailed flood protection scheme is under construction to protect Balclutha and some 23,000 acres of farm land from a possible 200,000-cusec flood.
The Roxburgh hydro-electric station was opened in July 1956 and control gates on Lake Wakatipu and Lake Hawea regulate the water supply. Smaller hydro-electric schemes within the catchment are on the Roaring Meg, Fraser, and Teviot rivers.
by James Wallace Ramsay, B.AGR.SC., Farm Planning Officer, Otago Catchment Board, Dunedin.