5 Conclusions
This report assesses the environmental, economic and social impacts of allocating to irrigation an amount of water that matches the provisions in the now defunct 1969 Order in Council. The assumption is made that after allowing for existing irrigation that a further 25,000 hectares could be irrigated with the quantity of water specified in the former Order in Council. The conclusions reached through this report are based on material sourced from existing publications, interviews with a number of people with knowledge of the area and the issues and limited analysis.
5.1 Environmental impacts
From an environmental perspective the establishment of a further 25,000 hectares under irrigation within the upper Waitaki could have both a positive and negative impact on the environment.
Wind erosion is a significant issue in the upper Waitaki catchment. One of the most significant impacts of further irrigation in this area will be a reduction in the amount of bare ground and corresponding reduction in wind erosion risk.
There is a significant risk of ground and surface water contamination in the upper Waitaki as a result of land use intensification through irrigation. This risk may be partly offset by the method of irrigation used and other improved land management techniques.
Irrigation will undoubtedly change the visual appearance of some areas within the upper Waitaki. However, much of the area that has been designated as suitable for irrigation will not be visible from the main highways, lessening the overall impact on visitors to the region.
While the ecological character of the upper Waitaki has been well documented no specific studies have been reported on the impacts of intensification on biodiversity values. Many areas within the upper Waitaki have already been protected as a result of the tenure review process and voluntary covenants. Irrigation may provide the opportunity to enhance further areas.
5.2 Economic impacts
The results of the analysis show that the options for irrigation from with the quantity of water specified in the former Order in Council produce considerable surplus in terms of net benefit from agricultural production, but a considerable loss in terms of hydro-generation.
Using base case assumptions the hydro losses are greater than the agricultural benefits in both scenarios of development. There is little difference in terms of agricultural outcomes between the two scenarios, but the electricity generation losses are 10 to 20 percent greater when irrigation development is concentrated in the upper part of the catchment.
The negative outcome overall is not changed by the discount rate used, but is very sensitive to the assumptions about agricultural returns and inputs including water use.
5.3 Social impacts
It is generally accepted that irrigation can transform society as well as land and landscapes. As land use intensifies through the upper Waitaki Catchment and land use changes occur it is expected that significant, mostly positive, social changes will also occur.
Under the base case used in the economic analysis, there was expected to be an increase of approximately 300 to 400 full-time equivalent (FTE) employees directly employed in agriculture (70/cumec), and an associated population gain of approximately 800 to 900 people (180/cumec). Value added, an indicator of economic activity, changes by approximately $12 to $13 million per annum [Although it should be noted that this does not include the change in added value associated with the lost energy generation, which would be substantial but largely does not affect the local economy.] ($2 to $3 million per cumec) directly associated with the increase in agricultural production. Further flow-on effects are expected in the local economy, but these have not been calculated.
