Otago region

The water quality results across Otago are spatially variable, water quality is best at lakes, river and stream reaches located at high or mountainous elevations under predominantly native cover. These sites tend to be associated with the Upper Lakes Rohe and the upper catchments of larger rivers (e.g., Lindis River, Pomahaka River, Nevis River) and the large lakes (e.g., Hawea, Whakatipu and Wanaka). Other areas, such as urban streams in the Dunedin, intensified catchments in North Otago and some tributaries in the Lower Clutha FMU have poorer water quality.

The distinctive and characteristic landscape of Otago includes the Southern Alps and alpine lakes, large high-country stations, dry central areas with tussock grassland and tors. There are dramatic coastlines around the Otago Peninsula and the Catlins and lowland pasture country is common in the west.

Approximately 23% of New Zealand’s lake surface area occurs in Otago and the region produces 17% of New Zealand’s hydroelectric generation. Despite large total water volumes present in the region, many areas of Otago are locally short of summertime water and irrigation is an important feature.

Rainfall throughout Otago is highly variable. Predominant westerly winds and strong mountainous influences caused by the Southern Alps result in the Clutha headwaters receiving up to 2,400 mm as an annual average. Central Otago receives much less rain lower due to the rain shadow effect of the Alps, with Alexandra and the Upper Taieri receiving on average less than 400 mm annually, the lowest totals in Otago.