Cardrona River

The Cardrona catchment lies between two contrasting climate zones: the drier Mediterranean climate of the Upper Clutha River/Mata-Au (average annual rainfall of 605mm) and the mountain climate, which is affected by the spill-over rain which crosses the Main Divide (average annual rainfall of 900mm).

The Wanaka-Cardrona Flats sit astride a sedimentary basin characterised by glacial deposits and glacial outwash gravels which contain the Wanaka Basin-Cardrona Gravel Aquifer. This aquifer is responsible for the flow of Bullock Creek through Wanaka Township, the availability of groundwater in the rural areas, and the periodic drying up of sections of the Cardrona River during summer. 

The Cardrona River can be separated into three main sections: a neutral reach (upstream of The Larches); a losing reach, in which surface water is lost to groundwater (between the Larches and SH6); and a gaining reach (downstream of SH6), in which surface flows are recharged from groundwater.

Land use in the Cardrona catchment consists of tussock and low producing grassland in the higher catchment, while in the lower catchment, high producing exotic grassland predominates. Sheep and beef farming on tussock dominates the catchment, with the high producing grasslands in the lower catchment supporting some deer farming.

Flood, border dyke, and more recently spray, irrigation is practised in the lower catchment. Most of the water used for irrigation is taken from the Cardrona River via water race intake structures. Originally intended for gold mining, the water races are now exclusively turned to pasture irrigation purposes and dominate the water management.

The Cardrona River, like many of Central Otago’s rivers, is recognised for both its scenic, recreational and biodiversity values. The Cardrona River supports four species of native fish (upland bully, longfin eel, koaro, and Clutha flathead galaxias) and three species of introduced sports fish (brown trout, rainbow trout, brook char). The lower reaches of the Cardrona River provide spawning and juvenile rearing habitat for a large number of brown and rainbow trout from the upper Clutha and Lake Dunstan. It is considered to be one of the most important sources of juvenile fish for those populations.