Executive Summary
This paper identifies and ranks the waterbodies of national importance for irrigation now and those under investigation to supply additional irrigation in the next 20 years.
The methodology used in this report is to be aligned with that used to define the national interest in the range of other values from waterbodies within the Waters of National Importance project of the water component of the Sustainable Development for New Zealand Programme of Action1.
The five waterbodies that currently contribute the greatest total value to farmgate GDP are:
- Heretaunga Plains – Hawke’s Bay
- Wairau catchment - Marlborough
- Rangitata River - Canterbury
- Waitaki River - Canterbury
- Central Canterbury groundwater - Canterbury
- The five waterbodies that have the potential to add the greatest amount to farmgate GDP after further irrigation development are:-
- Tukituki/Ruataniwha Plains – Hawke’s Bay
- Waitaki River - Canterbury
- Rakaia River - Canterbury
- Hurunui River - Canterbury
- Wairau catchment - Marlborough
The order of the list is based on aggregate farmgate GDP generated from the supply of irrigation water from the particular waterbody. The threshold for national interest was chosen as $5m for this study, as there is a natural break in the data at this point. It is recognised that incremental gains from irrigated agriculture are cumulative, so that for every hectare irrigated there is some gain in farmgate GDP, and that there may be other gains and also losses involved.
It is important to note that the values identified for current irrigation exist alongside the other values from those waterbodies identified in other reports within the Waters of National Importance study. In the same way, the potential for irrigation from waterbodies may be able to be realised without the loss of other values or indeed may create other benefits for those values. Irrigation benefit is not necessarily (but may be) gained at the expense of other values.
The potential area of irrigation and therefore of the value of some waterbodies for irrigation is limited by existing legislative conditions. For example, new water abstractions are limited by existing Water Conservation Orders on several waterbodies. In these cases, the true potential for additional irrigation is likely to be greater than is estimated here.
1 The Sustainable Development for New Zealand Programme of Action was released by the New Zealand Government in January 2003.
Contact for Enquiries
Water Programme of Action
Ministry for the Environment
PO Box 10-362
Wellington
or
Water Programme of Action
Ministry of Agriculture and Forestry
PO Box 2526
Wellington
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