This page has information on irrigated land in New Zealand. It can be useful for regional councils and water users who manage water takes and water quality in specific catchments because it maps the type and location of irrigation in detail for the first time.
This data is the most up to date snapshot of irrigated land across mainland New Zealand. The table below shows estimates of hectares irrigated in each region.
Table 1: Summary of irrigated area in different regions in 2017
| REGIONS | IRRIGATED AREA (HA) |
|---|---|
|
Canterbury
|
507,418 |
| Marlborough | 31,421 |
| Otago | 93,080 |
| Gisborne | 6,467 |
| Hawke’s Bay | 28,804 |
| Manawatu-Wanganui | 23,710 |
| Southland | 18,908 |
| Greater Wellington | 17,577 |
| Auckland | 7,958 |
| Bay of Plenty | 7,850 |
| Northland | 8,390 |
| Taranaki | 3,575 |
| Tasman | 11,924 |
| West Coast | 3,622 |
| Waikato | 23,740 |
Please note that Nelson was excluded as it is too small to contain significant irrigated areas.
Methodology
The dataset combines a number of different data sources, including:
- farm boundaries (using ownership data from Land Information New Zealand)
- aerial imagery (high resolution aerial and/or satellite photos)
- resource consent data (where available)
- analysis of satellite data (using normalised different vegetation index (NDVI) imagery)
- agricultural production statistics (sourced from Statistics New Zealand).
Uncertainty estimates for each region take into account a range of data limitations, for example missing data from the sources listed above.
A more detailed summary of the methodology is found within the report.
Limitations
This is a national overview, largely created through desk-top analysis. This means that the data should not be used at farm or irrigation-scheme scale in most regions without on-the-ground verification. We will increase the precision of estimates for future updates.
Map accuracy will vary between regions. In some areas it is difficult to identify irrigated land and irrigation system type. Reasons for this include, for example:
- there may be a lack of visual contrast between irrigated and non-irrigated land; or
- land used for short-rotation cropping may not be identifiable as irrigated if no crop was actively growing when the aerial photo or imagery was taken.
As this dataset uses a new methodology, caution is advised in making time series comparisons with earlier datasets on irrigated area – specifically, the estimates from the agricultural production statistics compiled by Statistics NZ and the Ministry for Primary Industries.