Rural water infrastructure

Rural water infrastructure in this context refers to water capture and storage, distribution, irrigation, and drainage infrastructure. This section focuses primarily on off-farm irrigation infrastructure, including storage infrastructure.

Description

Background, history, and institutional arrangements

Rural water infrastructure benefits food production and energy as well as urban supplies and amenity values. It supports a variety of agricultural industries such as horticulture, dairying, sheep, beef and cropping. Water capture, storage, distribution and drainage play an important role in increasing rural land productivity and maintaining agriculture's international competitive advantage by:

• smoothing the variability of water supply (due to intermittent rainfall and seasonal snow melts), which increases the amount, and reliability, of production per hectare, and allows exporters to take advantage of higher-value markets that require a reliable supply of high-quality products, and
• helping New Zealand adapt to climate change, as some areas are likely to become subject to increasing frequency and intensity of droughts and others become wetter.

Storage infrastructure ranges from large-scale dams and reservoirs to smaller-scale water tanks and groundwater extraction facilities.

There are several types of irrigation which vary in terms of efficiency of water distribution, waste and energy consumed. Over time, more efficient technologies have evolved with the development of border dyke, spray and micro irrigation. The most efficient irrigation technique for a particular region depends on a variety of factors, such as soil type and density, topography of the region, and the surface or groundwater take. The use of computers and technology advancements have also allowed greater specificity in water use, reduced waste, and diminished the labour demands on end users.

The majority of irrigation water is taken from surface water sources. Around 41% of irrigation water is extracted from groundwater sources, stored naturally in aquifers.

Irrigation accounts for the largest proportion of water consumption in the country. Of all the resource consents for water takes in New Zealand in 2006, 77% of allocated water was used for irrigation, as illustrated.

Figure 44: Use of allocated water in New Zealand, 2006

Source: Ministry for the Environment, Environment New Zealand 2007

Irrigation schemes and/or on-farm irrigation exist in Northland, Auckland, the Waikato, Bay of Plenty, Hawke's Bay, Taranaki, the Wairarapa, Nelson, Marlborough, Canterbury, Otago, and Southland.[118] Most are on the east coast, as New Zealand's mountainous topography means more precipitation falls on the west coast.[119] Around 500,000 hectares of land is irrigated in New Zealand, approximately 350,000 hectares of which is in Canterbury.[120] The following table shows the area of irrigated hectares by region.

Large-scale irrigation in New Zealand began in the late 19th century. During the Great Depression of the 1930s, several large-scale storage and irrigation projects, such as the Rangitata Diversion Race, were built using government funding. The majority of major schemes were constructed after 1960 in the Canterbury and Central Otago regions.

The following map shows government-owned irrigation schemes prior to 1989, and the number of hectares they irrigated. It excludes on-farm irrigation owned by private individuals or entities.

Figure 45: New Zealand irrigation schemes - formerly government-owned schemes only

Source: Original data is from Martin, G., and Lewthwaite, W., (1987), "Review of Existing Irrigation Schemes in New Zealand with a view to the future", Appendix 2.

The rationale for government involvement in developing, subsidising and maintaining community irrigation schemes changed from period to period:

• Between 1910 and 1935, New Zealand government involvement followed the history of government assistance of irrigation by colonial governments in Australia. Policies aimed to mitigate drought, take advantage of existing water rights and reclaim mining land.
• After 1935, the first Labour government expanded the irrigation programme to boost employment and make greater use of the water resource.
• In the 1950s, a Select Committee concluded that direct government intervention was necessary because individual farmers could not obtain the required finance, technology and labour, despite concerns being raised about the financial implications of the schemes.
• From the 1960s to 1980s, community schemes were increasingly viewed as a farm management tool to intensify agricultural production, and new irrigation schemes were justified as being in the national interest by virtue of having economy-wide benefits.[123]

In 1987, questions were raised about the national benefit and central government's ability to manage and recover costs. A risk that government intervention could distort incentives and crowd out private investment also became apparent.

In 1988, central government began to transfer ownership of the Crown schemes to farmers. The final scheme, the Beggs Scheme in Central Otago, was sold approximately 18 months ago. No schemes remain in Crown ownership.

In 1991, responsibility for approving schemes was devolved to local government under the Resource Management Act 1991. Central government has focused its efforts on funding science and technology development, and on facilitating the planning and proposal development process, through initiatives such as the Sustainable Farming Fund and the Community Irrigation Fund.

Several major schemes have been developed since devolution, including Opuha (1998, 16,000 ha), Waimakariri (1999, 18,000ha), North Otago Stage 1 (2006, 10,000ha), and the Wai-iti Valley Augmentation Dam (800,000m2), which also opened in 2006.