July 30, 2013
Study confirms generally high quality of water in Waianakarua catchment
Otago Regional Council monitoring of the Waianakarua catchment in North Otago has highlighted that water quality and fish habitat there is generally very good.
ORC undertook a nine-month sampling programme in 2012 to gain a better understanding of the existing water quality, habitat quality, and ecological values in the catchment.
The results were measured against the water quality standards notified in Plan Change 6A to the Otago Water Plan. These standards ensure that water will be of suitable quality for a variety of purposes, such as swimming, fishing, stock drinking water, and mahika kai.
The study highlighted that the mostly good to excellent water quality in the catchment sustains a thriving and diverse fish community, including some species which have been officially classified as ‘at risk’ or ‘declining.’
However, the nutrient Nitrate-Nitrite Nitrogen (NNN) often exceeded the river standard expected in the Water Plan change.
ORC director of environmental information and science John Threlfall said existing intensification of land use, with several dairy farms operating near the mouth of the river, and proposals for further intensification in areas upstream of State Highway 1, had the potential to adversely affect water quality in the lower part of the river.
However, Plan Change 6A was designed to limit the effects of this intensification, by encouraging land managers to ensure best environmental farm practices were operating to minimise contaminants coming into waterways from their rural land.
Dr Threlfall said the Waianakarua study was an important opportunity to compare a catchment study with the new standards in the Water Plan.
Such comparisons would allow ORC staff to refine their advice to farmers on the farming practices needed to maintain or improve water quality, by focusing on the places where those improvements were most needed, he said.