Clarence River (Waiau Toa )

Last Modified: 16-5-2019 22:05


Clarence River at dawn near its confluence with the Acheron River
Clarence River at dawn near its confluence with the Acheron River
© Christopher Cookson  License this image

The Clarence River (Waiau Toa),  the longest river in Marlborough at 230km in length and eighth longest in NZ, has its source as the outlet of Lake Tennyson reaching the sea in northern Kaikoura District at the Clarence Delta. Parts of the river flow through the Marlborough District, including several major tributaries including the Acheron River. The Clarence/Waiau Toa drains a catchment of around 3,300km2. The Clarence River flows initially south from Lake Tennyson, before flowing east then north for short distances, before flowing in a north-easterly for most of its length, until near the end of its lower gorge, it changes to a south-easterly direction, and then south-west on emerging from its gorge, before finally flowing south-east again to its mouth.

The river has braided sections, as well as extensive lengths of narrow gorge. The braided sections form an important breeding habitat for a number of bird species including banded dotterel and black fronted tern.

The river is popular for rafting, with easy grade 2 and 3 rapids, and also provides opportunities for trout fishing, however it has been infested with the invasive algae Didymo. In the riparian zone, management of pest plant species such as broom and gorse is an ongoing concern. Wilding conifers are a problem in the wider area.The surrounding landscape supports populations of deer, pigs, and goats which offer hunting opportunites with appropriate permits.

The river was featured in a 2010 television documentary narrated by Craig Potton produced by South Pacific Pictures.

The river is bridged near Hamner on the Acheron Road, and on State Highway One near the Kaikōura Coast by a 302m concrete span two lane bridge that replaced an earlier single lane wooden bridge  a short distance upstream. A few hundred metres downstream of the State Highway One road bridge is a railway bridge.

Following a magnitude 7.8 earthquake in November 2016, a bridge in the Clarence Valley was destroyed, cutting road access to the upper valley, and large dams formed by land slips caused by the earthquake caused temporary lakes which later breached.


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Cookson, C. (2019). Clarence River (Waiau Toa ). Retrieved May, 29, 2024, from