Physical Stock Accounts for Water Released

Physical Stock Accounts for Water Released

Statistics New Zealand has released the first physical stock accounts for freshwater. The accounts are part of a series of environmental accounts being developed for natural resources, including energy and minerals, fish, forestry and water.

The water accounts show volumes for inflows (rain, snow, sleet, hail and other sources), storage changes (water held in the soil, lakes, glaciers and other places), and outflows (mostly flows to the sea or evaporation to the air).

The volumes are at national and regional levels for the June years 1995 to 2001. For the year to June 2001, New Zealand’s freshwater inflows amounted to 407 billion cubic metres. However, the storage volume fell by 15 billion cubic metres, mostly because of low soil moisture at the end of June 2001. As a result, outflows were estimated at 422 billion cubic metres.

The accounts can assist in assessing how much water is available for use. For example, the wettest region in the year ended June 2001 was the West Coast, with an inflow of 75 billion cubic metres of water. By contrast, the inflow to the Waikato region, which has a slightly larger land area, was only half that amount.

The accounts can also be used to monitor climate change. The El Niño years of 1997 and 1998 clearly show up as times when inflows were lower than normal. In future, if the monetary value of water can be measured, then water use could be linked to economic statistics such as Gross Domestic Product (GDP) to show its economic impact.

The accounts were produced in association with the Ministry for the Environment (MfE). Data and advice were provided by the National Institute of Water & Atmospheric Research (NIWA), the Institute of Geological & Nuclear Sciences (GNS), Otago University and other organisations. The accounts and associated reports are available on the Statistics New Zealand website.

Brian Pink
Government Statistician

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