Managing water resources means grappling with questions such as who has rights to the available water, how to manage those rights, and how to protect the environment.
The Resource Management Act 1991 requires regional councils to manage water resources in a sustainable manner. A major problem for councils is defining standards to measure environmental conditions – for example, if the water in a particular river dropped below a certain level then no more water should be taken. However, there has been uncertainty over how to decide what such standards should be, and who should set them.
Sustainable Water Programme of Action
From the 1990s and into the 2000s, increased demand for water and decreased water quality has shown a need for better management of water resources. Regional councils called for greater leadership from central government. In 2003 government responded with the Sustainable Water Programme of Action, which is coordinated by the Ministry for the Environment and the Ministry of Agriculture and Forestry.
The programme aims to deal with increasing demand for water by encouraging efficient water management, working with local government and communities, and developing standards. National policy statements provide direction, and national environmental standards allow monitoring.
Regional councils, power generation companies, GNS Science and the National Institute of Water and Atmospheric Research maintain an extensive network of climate and water monitoring sites throughout the country.
Water allocation means dividing available water resources across competing or conflicting uses. In New Zealand, there is a ‘first come, first served’ principle. The water allocation process is defined in regional council policies and plans. Decisions are made through resource consent hearings and rules in district plans.
In some rivers, water allocation limits have been determined by water conservation orders, which aim to preserve specific water bodies in their natural state (or as close as possible to it) to protect recreational or natural features. In 2008 there were 14 water conservation orders, with the most recent (2006) providing protection for the Rangitātā River in South Canterbury.
Almost 80% of the water extracted in New Zealand is used for irrigation for viticulture, horticulture, dairying, beef and sheep farming, and cropping. There is approximately 500,000 hectares of irrigated land in New Zealand, almost one-third of which is used for dairying. In recent years, dairying has expanded into drier areas such as Canterbury, requiring considerable amounts of water for irrigation.
The annual value of irrigation water in terms of increased agricultural production is estimated to be around $800 million.
Greening the land
Irrigation has become widespread on the dry east coast of the South Island, but is not new. Duntroon farmer Sid Hurst recalled that ‘he has always known what water could do for farmers on the Waitaki plains. As a young lad he helped siphon water illegally out of the Oamaru Borough race to wild flood paddocks. The response was dramatic. Irrigated areas turned green and flourished, creating a stark contrast with the arid brown of surrounding paddocks.’ 1
Effects of taking water
Removing water from a river obviously reduces the quantity that will be flowing downstream. It can also reduce water quality, as there is less water to flush away solutes (dissolved substances) and sediments. Rivers can also flow more slowly, and become shallower and warmer, making it easier for algae to grow and less suitable for fish and other aquatic life.
One of the major issues affecting water resources management is the limited information available on volumes of water actually taken. Good records of water allocation are kept but there has often been either more or less water used than what was actually allocated.
A new national environmental standard for water-measuring devices will greatly improve measurements of how much water is actually taken.