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Fresh water
Freshwater demand (allocation)
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New Zealand has an abundance of fresh water, however not all of the renewable resource is actually available to be used – much of it needs to be retained in the rivers, lakes and aquifers to maintain the ecological, recreational, or cultural values of these water bodies. Furthermore, water is not always in the right place at the right time for users. A large proportion of New Zealand’s annual rainfall occurs in winter, when demand is relatively low. In addition, water availability and demand vary regionally. Eastern regions of the country tend to have less rainfall than western regions and have a high demand for water for irrigation.
The freshwater demand environmental indicator in New Zealand reports on the volumes of water allocated to human uses through resource consents. This is known as total consumptive water allocation. ‘Consumptive’ means that the water taken is not returned to the source.
Current situation
In 2010, there were more than 20,500 resource consents for taking water. Around two-thirds of consents permit taking water from groundwater sources, however, the volume of water allocated from surface water sources (rivers and streams) is four times higher than from groundwater sources.
The total amount of consumptive water allocated in New Zealand in 2010 was 27 billion cubic metres. This is equivalent to almost half the volume of Lake Taupo.
Use of fresh water
In 2010, the majority of consumptive weekly allocations were for irrigation (46 per cent) and hydro generation (41 per cent). The remainder is shared among public drinking water supply, industry and stock watering. All of the volume for the hydro generation is for the Manapouri hydro take in Southland, which discharges the allocated fresh water to sea.
Use of weekly allocated water in New Zealand, 2010
Data source: Ministry for the Environment.
Regional and seasonal allocation use
Peak water allocation pressure occurs during summer when consents for irrigation are active. In 2010 the total water allocated each week was 757 million cubic metres. This volume is sufficient to fill up 30 Olympic-sized swimming pools every minute.
The Canterbury, Southland and Otago regions account for 86 per cent of the total weekly consumptive allocation in New Zealand. While most of the allocated water in Southland is for hydro generation, the main water use in Canterbury and Otago is for irrigation. Other regions such as Auckland, West Coast and Nelson have the majority of their allocated water for public drinking water supply and manufacturing processes.
Regional variations in the use of allocated water, 2010
Data source: Ministry for the Environment.
Note: Allocations for stock drinking water are underestimated because the majority of stock drinking takes are non-consented as this is generally a permitted activity under the Resource Management Act 1991.
Trends
National weekly water allocation has increased by a third between 1999 and 2010. If the Manapouri hydro take in Southland is excluded, allocation (to uses such as irrigation) has nearly doubled since 1999, and increased by 10 per cent in the last 4 years.
Between 1999 and 2010, the largest increase in allocated volume was in Canterbury with a growth of 98.2 million cubic metres allocated per week (65 per cent change).
The highest percentage increase in more recent years (2006–2010) has occurred in Manawatu-Wanganui (51 per cent) followed by Northland (41 per cent).
Changes in regional weekly allocation (Mm3/week) between 1999, 2006 and 2010
Data source: Ministry for the Environment.
Note: A different scale is used on the lower chart
The increase in total water allocation in New Zealand since 1999 can largely be explained by the increase in demand for irrigation. The amount of land irrigated by consented water takes has increased by 82 per cent between 1999 and 2010.
Actual water used
The percentage of estimated actual water used compared with the maximum allocated volume in New Zealand is around 65 per cent. However, most regions use less than 50 per cent of their allocated water. The highest percentages of actual use compared to the allocated volumes were in Gisborne (192 per cent), Southland (74 per cent) and Canterbury (57 per cent).
On the basis that allocations have been sustainably set, this highlights that there are opportunities for more efficient utilisation of allocated water in New Zealand.
Water take data is critical in providing the information needed to efficiently manage water resources. One mechanism in place is the new Resource Management (Measurement and Reporting of Water Takes) Regulations 2010, which will provide decision-makers with more accurate information on actual water use.
Actual water used compared to consented annual volumes (Mm3/year) for each region in 2010
Data source: Ministry for the Environment.
Note: The figure for Gisborne suggests that actual use is almost double the consented allocation. This is because the water meter which measures the municipal consent used in this estimation, measures a combined intake from a dam and a stream for the city water supply. It is only the take from the dam that is consented. Therefore although the actual water usage appears high in Gisborne, it does not indicate that the consent limit is breached.
International comparison
Compared internationally, New Zealand has an abundance of fresh water. New Zealand is ranked 4th out of 30 OECD countries for the size of its renewable freshwater resource on a per capita basis. Within New Zealand, allocated water comprises less than 5 per cent of its renewable freshwater resource.
In 2007 New Zealand had the 2nd highest water abstraction per person out of 26 OECD countries. This result reflects our low population and relatively high use of consented water for agricultural irrigation. However, latest available data shows that New Zealand had the third lowest water withdrawal as a share of total water available out of 29 countries in the OECD. This shows that although abstraction may be high per capita, there is a plentiful water resource available at a national level.
Ranking of water abstraction per capita for OECD countries in 2007
Data source: OECD. 2010. OECD Factbook 2010. Economic, Environmental and Social Statistics, Paris: OECD.
Ranking of water withdrawals as a percentage of gross annual availability for OECD countries (using latest available data).
Data source: OECD. 2009. OECD in Figures 2009. Paris: OECD. OECD data spreadsheet.
In 2006, the OECD average for total weekly allocation of water used for irrigation was 43 per cent. In the same year, New Zealand’s average total weekly allocation for irrigation was much higher at 77 per cent. The use of water by manufacturing and industry and for public water supply is generally low in New Zealand compared with more populous countries in Europe and North America.
The latest information on allocation in New Zealand can be seen in the following publication: Update of Water Allocation Data and Estimate of Actual Water Use of Consented Takes 2009–10.
Return to the main freshwater page.
Last updated: December 2010
