Water resources review: Winter 2004 (June to August 2004)
River flows were well below normal in Northland and Auckland, with some catchments having their driest winter on record. Flows were above normal in the central and southern North Island, with very high flows in some places. Buller and coastal Southland rivers were also above average, while flows were near normal in the rest of the South Island.
Stream water clarity was near normal for much of New Zealand, but lower than usual in the Wellington region, and higher than usual in Northland, where the low flows meant there were fewer floods to stir up sediments.
Stream temperatures were 1–2°C lower than usual in Northland and Auckland, but typically 1°C warmer than normal in South Canterbury and coastal Otago. Temperatures in most other places were near normal.
Lake levels were generally higher than usual for most of the country, except in the upper North Island, where levels were normal or below normal.
Groundwater levels showed the usual winter increases. Levels in the west of the North Island were generally higher than normal, reflecting the autumn rainfall. Levels in the South Island were generally below average in the east and above average in the south and west. Levels in the rest of New Zealand were generally average for the time of year.
Water resources information provided by NIWA field teams, regional and district councils, and hydropower companies. Groundwater data supplied by the Institute of Geological & Nuclear Sciences.