5 Conclusion
This report covers a broad range of issues, many of which are the focus of more detailed studies. The inherent nature of forecasting with the considerable number of unknowns should be noted in an exercise such as this. It should also be noted that taking a position on a regional basis may ignore more localised situations, which can be the opposite of the region as a whole. For example the Otago and Marlborough regions have a potentially available supply that exceeds current and expected future demand, however when this is broken down to a catchment basis, there are large areas where a deficit situation exists owing to the difficulty in accessing the water supply. Calculating water supply and demand according to a particular catchment is the next logical step and may be more useful to determine an overall regional picture.
That said, the focus of this report is to present the impact on water demand of the market demand pull factors, and it is possible to draw on some carefully considered estimates concerning the likely growth in demand for water driven by economic considerations and apply these to each region.
- Based on assessments of the specific agricultural sectors and their respective market prospects to 2010, there is likely to be increased landuse in dairy, horticulture, viticulture and forestry with irrigation requirements increasing accordingly for all but forestry. The 'other pasture' landuse will decline, however within this category deer farming will increase significantly. The impact of this on irrigation requirements is expected to be limited.
- Sheep and beef farming will see greater competition from dairy, horticulture, viticulture and lifestyle blocks for high quality land. This will in turn encourage more effective use of a dwindling supply of suitable beef and sheep finishing land. New planting of forestry will grow at a lower rate than in previous decades and be confined to the more marginal pastureland. Restocking of harvested forestry areas will increase.
- The desire for greater control over the variables impacting on an agricultural venture will lead many landowners to water as a solution. This is particularly relevant to landowners in drought prone regions of Canterbury, Otago, Marlborough, south Wairarapa and Hawkes Bay where water is essential for many agricultural enterprises.
- Access to irrigation generally reduces commercial risk and with this in mind the demand for water for agricultural production purposes will increase by an estimated 28 percent in the period to 2010. The estimated increase in new irrigation area is just under 150,000 hectares and does not include intensification of irrigation on irrigated land.
- The Canterbury region dominates the current share of irrigated agricultural land with 68 percent followed by Otago with 13 percent. The dominance of these two regions will continue, however other regions will also increase the areas irrigated on a localised basis where soil type, contour and access to irrigation allow.
- The major drivers for landuse change and the increased irrigation requirement are economic, with landowners looking to maximise the return on capital invested in agriculture. Leading the charge is the expansion of the dairy industry at an estimated 16 percent growth out to 2010. Dairy landowners are seeking cheaper land and irrigation provides the means to allow the projected expansion to be satisfied.
- The demand for high quality land is intensifying. Irrigation allows more medium quality land to be upgraded to high quality, providing landowners with an increased range of landuse options. As the demand pressure on water increases the economic value (and therefore costs) will increase. These economic considerations will likely prevent demand exceeding supply.
- Mapping technology has allowed for increased knowledge of soil type distributions and properties (in particular soils with low water holding capacity (predominantly North Island) that will potentially benefit from irrigation). This will assist landowners in their decisions on whether to irrigate.
- The growth in dairying will result in increased use of fertilisers on newly converted land. This will have environmental implications for regional water supplies in terms of water quality. Increased nitrate monitoring requirements will likely be applied to dairy farming and horticulture in particular as well as other intensive land use operations.
- The growth in demand for water resources will increase the conflict between agricultural use, amenity use, industrial use, recreation and environmental preservation. Regional water allocation systems will be under greater scrutiny as a result.
The myriad of issues surrounding water allocation makes this a complicated issue. With the increasing value of water in determining landuse, the conflict between the various groups promoting either economic or non-economic value is set to increase. The pressure on water resources is set to rise considerably. These pressures may impact on the vision of landuse change as presented earlier in this report however, the extent is obviously uncertain.
With the exception of the Hawkes Bay region, the vision for landuse change can be accommodated within the potentially available water supply levels. For the vision to be achieved in the Hawkes Bay, a constructive reappraisal of the water allocation policy will be required. Growth in Waikato, Marlborough and Otago regions will also be reliant on the ability to relocate water cost effectively from the major rivers that dominate surface water supplies in these three regions.
With regional councils playing a key role in the expansion of irrigation it is perhaps useful to list the issues they face:
- Setting minimum river flows or groundwater levels,
- The economic and social impact of limits being set on the total amount of water that can be allocated
- Allocation policies and inter-regional attitudes toward irrigation of agricultural land
- The need for more scientific evidence to support restrictive allocation policies
- Dealing with over-allocated resources
- Promoting efficient use. Allocating water permits according to soil type or crop usage (crop evapotranspiration rates to become a consideration in the allocation process)
- With irrigators not charged for water they pump themselves, the level of interest in bores on private land is likely to increase further (in particular, the impact on the aquifers in each region from the increased off-take from private bores).
- The impact of cost on water use efficiency levels
- Tradeable water rights
- Environmental impacts in terms of water quality (nitrate levels), habitat loss from diversion, flood risk due to damming and diverting watercourses.
While the above list is not exhaustive it highlights the range of difficulties in fairly and equitably allocating a limited resource. This report is not charged with analysing the rights and wrongs of particular allocation polices applied in New Zealand, however, in compiling the report it is apparent that there is a very real need to have a clear picture of our national water resource. A consistent system of capturing and recording meaningful data on our ground and surface water resources is required. Such a system could require consent returns to be filed with a centralised database in a standardised form. Conceivably, this would enhance the pool of information regarding our natural freshwater resources.
The next logical step is for a supply and demand assessment within each catchment. This will more clearly identify the water surplus/deficit situation and provide a base from which community irrigation schemes could be considered.
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