Ōhau River (Canterbury)

The Ōhau River is a river in the Mackenzie Basin of New Zealand's South Island. It is the primary outflow of Lake Ōhau, from which it flows in a roughly eastward direction until reaching the artificial Lake Benmore after a distance of roughly 27 kilometres (17 mi). In 1981, the artificial Lake Ruataniwha was created along the river's length to power a small hydroelectric power station as part of the Waitaki hydro scheme.^[1] Prior to the creation of the Waitaki hydro scheme, the river flowed directly into the Waitaki River rather than through a series of lakes.^[2] The river forms part of the traditional boundary between Otago and Canterbury regions.^[3]

Ōhau River
Ōhau River upstream of Lake Ruataniwha
Location
Country	New Zealand
Physical characteristics
Source	Lake Ōhau
• coordinates	44°17′06″S 169°56′11″E / 44.2851°S 169.9365°E
• elevation	540 metres (1,770 ft)
Mouth	Lake Benmore
• coordinates	44°20′39″S 170°12′17″E / 44.3441°S 170.2048°E
• elevation	380 metres (1,250 ft)
Length	27 km (17 mi)
Basin features
Progression	Lake Benmore→ Lake Aviemore→ Lake Waitaki→ Waitaki River→ Pacific Ocean
Tributaries
• left	Twizel River
• right	Wairepo Creek
Waterbodies	Lake Ruataniwha

Prior to European settlement of the region, the river was a traditional mahinga kai (food gathering site) for Māori travelling through the Mackenzie Basin, providing valuable food sources such as weka, tuna (eels), and pora (Brassica rapa subsp. sylvestris)^[4][5]