New Zealand Journal of Forestry (2013) 58(2): 27–30
©New Zealand Institute of Forestry

Feature article
Recent changes in the water quality of Lake Taupo and its inflowing streams

Bill Vant <sup>1

1</sup> Scientist, Waikato Regional Council, Hamilton

More than 10 years ago, the Waikato Regional Council became concerned about the likely effects of changes to land use in the catchment of Lake Taupo on the water quality of the lake. Conversions of sheep and beef farms to dairying and of pine plantations to farms, together with a steady intensification of farming, were all considered to be likely causes of the increases in nitrogen concentrations in rivers and streams in parts of the region and in New Zealand in general. Previous studies had shown that the algae in Lake Taupo were frequently nitrogen deficient, and that the experimental addition of nitrogen increased the amount of algae present in the lake’s water. As a result, increases in the loads of nitrogen entering Lake Taupo were identified as a threat to lake water quality. Calculations showed that over 90 per cent of the manageable nitrogen entering the lake came from areas of pasture in the catchment.
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