Water is relatively abundant in New Zealand due to the temperate climate and maritime weather patterns. In recent years, water pollution and draw-down of aquifers have become important environmental issues in New Zealand.
Water is relatively abundant in New Zealand due to the temperate climate and maritime weather patterns. In recent years, water pollution and draw-down of aquifers have become important environmental issues in New Zealand.
In New Zealand, there are more than 425,000 km (264,000 mi) of rivers and streams and about 4,000 lakes and over 200 underground aquifers. Annual water flow is 145 million litres per person. [1] The reliable supply of good water is an important economic advantage for New Zealand, but its quality and availability is declining. [2]
There are 3,820 lakes in New Zealand with a surface area larger than 1 hectare (2.5 acres), [3] and are of varying types and origins. Many of the lakes in the central North Island area are volcanic crater lakes, while the majority of the lakes near the Southern Alps were carved by glaciers. Hydroelectric reservoirs are common in South Canterbury, Central Otago and along the Waikato River.
Over 180,000 km (110,000 mi) of rivers has been mapped in New Zealand, [4] the longest being the Waikato River with a length of 425 kilometres and the largest river by volume is the Clutha River with a mean discharge of 533 cubic metres per second. [5]
New Zealand has many notable waterfalls, some of which are regularly visited by tourists. Huka Falls on the Waikato River is one such waterfall. Sutherland Falls is usually regarded as the highest waterfall in New Zealand at 580 metres high but Browne Falls cascades 619 m or 836 m depending on what is considered to be the source. The Maruia Falls on the Maruia River are a relatively new waterfall formed as a result of the 1929 Murchison earthquake. [6]
The average annual precipitation for New Zealand as a whole is 2.1 m (6 ft 11 in). In mountain portions of the West Coast, it exceeds 10 m per year. The distribution of precipitation across the country is determined by its location with the mid-southern latitudes and its topography. Seasonal differences in precipitation are substantial, regularly leading to summer water deficits in many parts of the country, though the season of greatest and least precipitation differ from region to region. The amount of precipitation also varies interannually in response to both El Niño–Southern Oscillation and Interdecadal Pacific Oscillation cycles.
Water resources are used for a number of purposes, including hydroelectricity generation, irrigation, and municipal water supply. Approximately 2% of New Zealand's freshwater resource is allocated for consumptive use.
The supply of water to consumers is provided by local government territorial authorities, which include city councils in urban areas and district councils in rural areas. The legal framework includes the Health Act 1956, amended in 2007, the Local Government Act 2002 and the Resource Management Act 1991.
The Resource Management Act 1991 governs the use of water (and other natural resources). A resource consent is required for taking, damming, discharging and diverting water. There is a National Policy Statement for Freshwater Management. [7]
In modern times, the quantity, quality and timing of water within New Zealand has been changing. Principal causes have been abstraction, impoundment, land use and land cover change, and agricultural and industrial runoff.
Water pollution in New Zealand is becoming an increasing concern for environmentalists and for regulatory bodies.
An increase in dairy farming is linked to an increase in water pollution,[ citation needed ] and siltation due to land clearance has affected lakes, rivers, caves and bays. There are more than 800 water quality monitoring sites around New Zealand that are regularly sampled.
Various organisations in New Zealand are involved with water and its use. Regional Councils have the statutory responsibility for water.
Hydrology is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and environmental watershed sustainability. A practitioner of hydrology is called a hydrologist. Hydrologists are scientists studying earth or environmental science, civil or environmental engineering, and physical geography. Using various analytical methods and scientific techniques, they collect and analyze data to help solve water related problems such as environmental preservation, natural disasters, and water management.
A drainage basin is any area of land where precipitation collects and drains off into a common outlet, such as into a river, bay, or other body of water. The drainage basin includes all the surface water from rain runoff, snowmelt, hail, sleet and nearby streams that run downslope towards the shared outlet, as well as the groundwater underneath the earth's surface. Drainage basins connect into other drainage basins at lower elevations in a hierarchical pattern, with smaller sub-drainage basins, which in turn drain into another common outlet.
The Waikato River is the longest river in New Zealand, running for 425 kilometres (264 mi) through the North Island. It rises on the eastern slopes of Mount Ruapehu, joining the Tongariro River system and flowing through Lake Taupō, New Zealand's largest lake. It then drains Taupō at the lake's northeastern edge, creates the Huka Falls, and flows northwest through the Waikato Plains. It empties into the Tasman Sea south of Auckland, at Port Waikato. It gives its name to the Waikato region that surrounds the Waikato Plains. The present course of the river was largely formed about 17,000 years ago. Contributing factors were climate warming, forest being reestablished in the river headwaters and the deepening, rather than widening, of the existing river channel. The channel was gradually eroded as far up river as Piarere, leaving the old Hinuera channel through the Hinuera Gap high and dry. The remains of the old course are seen clearly at Hinuera, where the cliffs mark the ancient river edges. The Waikato's main tributary is the Waipā River, which converges with it at Ngāruawāhia.
Environmental degradation is the deterioration of the environment through depletion of resources such as quality of air, water and soil; the destruction of ecosystems; habitat destruction; the extinction of wildlife; and pollution. It is defined as any change or disturbance to the environment perceived to be deleterious or undesirable.
The law of water balance states that the inflows to any water system or area is equal to its outflows plus change in storage during a time interval. In hydrology, a water balance equation can be used to describe the flow of water in and out of a system. A system can be one of several hydrological or water domains, such as a column of soil, a drainage basin, an irrigation area or a city. Water balance can also refer to the ways in which an organism maintains water in dry or hot conditions. It is often discussed in reference to plants or arthropods, which have a variety of water retention mechanisms, including a lipid waxy coating that has limited permeability.
The rivers of New Zealand are used for a variety of purposes and face a number of environmental issues. In the North Island's hill country the rivers are deep, fast flowing and most are unnavigable. Many of the rivers in the South Island are braided rivers. The navigable rivers were used for mass transport in the early history of New Zealand.
In hydrology, the inflow is the water entering a body of water. It can also refer to the measure of average volume of incoming water per unit time. It is contrasted with outflow.
Water resources are natural resources of water that are potentially useful for humans, for example as a source of drinking water supply or irrigation water. 97% of the water on the Earth is salt water and only three percent is fresh water; slightly over two thirds of this is frozen in glaciers and polar ice caps. The remaining unfrozen freshwater is found mainly as groundwater, with only a small fraction present above ground or in the air. Natural sources of fresh water include surface water, under river flow, groundwater and frozen water. Artificial sources of fresh water can include treated wastewater and desalinated seawater. Human uses of water resources include agricultural, industrial, household, recreational and environmental activities.
A stream is a continuous body of surface water flowing within the bed and banks of a channel. Depending on its location or certain characteristics, a stream may be referred to by a variety of local or regional names. Long large streams are usually called rivers, while smaller, less voluminous and more intermittent streams are known as streamlets, brooks or creeks.
In New Zealand "dirty dairying" refers to damage to the ecological health of New Zealand's freshwater environment by the intensification of dairy farming, and also to the high profile campaign begun in 2002 by the Fish and Game Council to highlight and combat this.
The following outline is provided as an overview of and topical guide to hydrology:
Water pollution in New Zealand is an increasing concern for those who use and care for waterways and for New Zealand regulatory bodies. An increase in population is linked to an increase in water pollution, due to a range of causes such as rural land use, industrial use and urban development. Fresh water quality is under pressure from agriculture, hydropower, urban development, pest invasions and climate change. While pollution from point sources has been reduced, diffuse pollution such as nutrients, pathogens and sediments development and from stormwater in towns is not under control. There are more than 800 water quality monitoring sites around New Zealand that are regularly sampled.
Water resources management in Belize is carried out by the Water and Sewerage Authority (WASA) in most cases. One of the primary challenges the country is facing with regard to water resources management, however, is the lack of coordinated and comprehensive policies and institutions. Furthermore, there are various areas of water management that are not well addressed at all such as groundwater data and provision of supply. Data on irrigation and drainage is not adequately available either. Demand on water resources is growing as the population increases, new economic opportunities are created, and the agriculture sector expands. This increased demand is placing new threats on the quality and quantity of freshwater resources. Other constant challenge for management entities are the constant threat of floods from tropical storms and hurricanes. The Belize National Emergency Management Organization (NEMO) is charged with flood management as they occur but it is unclear what institution has responsibility for stormwater infrastructures.
The Whangamarino Wetland in the Waikato District is the second largest wetland complex of the North Island of New Zealand. Encompassing a total area of more than 7200 hectares, the Department of Conservation Te Papa Atawhai manages 5,923 hectares of peat bog, swamp, mesotrophic lags, open water and river systems listed as a wetland of international importance under the Ramsar Convention. Fish and Game New Zealand are the second largest landowner, managing 748 hectares of the wetland primarily as gamebird hunting habitat.
National Institute of Hydrology (NIH) is an autonomous society under Ministry of Water Resources, River Development & Ganga Rejuvenation, Government of India and has been functioning as a research Institute in the area of hydrology and water resources in the country since 1979 in Roorkee City. Main objectives of the institute are to undertake, support, promote and coordinate systematic and scientific research work in all aspects of Hydrology and Water Resources.
Lake Disappear is an intermittent volcanogenic lake situated in the North Island of New Zealand, just over 20 km from Raglan, 4 km beyond Bridal Veil waterfall. It has also been described as a solution lake. The south end can be seen from Kawhia Rd and, when the north end is full, it can be seen from the point which is at the end of Plateau Rd on the Pipiwharauroa Way. It is the largest known polje in the country, though another large one is in Paparoa National Park.
Water quality in Taranaki is a notable environmental issue for many stakeholders with concerns about the potential impact from dairy farming in New Zealand and petrochemical industries.
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include non-salty mineral-rich waters such as chalybeate springs. Fresh water may encompass frozen and meltwater in ice sheets, ice caps, glaciers, snowfields and icebergs, natural precipitations such as rainfall, snowfall, hail/sleet and graupel, and surface runoffs that form inland bodies of water such as wetlands, ponds, lakes, rivers, streams, as well as groundwater contained in aquifers, subterranean rivers and lakes. Fresh water is the water resource that is of the most and immediate use to humans.
The effects of climate change on the water cycle has important knock-on effects on the availability of freshwater resources, as well as other water reservoirs such as oceans, ice sheets, atmosphere and land surface. The water cycle is essential to life on earth and plays a large role in the global climate and the ocean circulation. The warming of the earth is expected to cause changes in the water cycle for various reasons. A warmer atmosphere can contain more water vapor which has effects on evaporation and rainfall. Oceans play a large role as well, since they absorb 93% of the increase in heat since 1971. This has effects on the water cycle and on human society, since the ocean warming directly leads to sea level rise.
Susanna Wood is a New Zealand scientist whose research focuses on understanding, protecting and restoring New Zealand's freshwater environments. One of her particular areas of expertise is the ecology, toxin production, and impacts of toxic freshwater cyanobacteria in lakes and rivers. Wood is active in advocating for the incorporation of DNA-based tools such as metabarcoding, genomics and metagenomics for characterising and understanding aquatic ecosystems and investigating the climate and anthropogenic drivers of water quality change in New Zealand lakes. She has consulted for government departments and regional authorities and co-leads a nationwide programme Lakes380 that aims to obtain an overview of the health of New Zealand's lakes using paleoenvironmental reconstructions. Wood is a senior scientist at the Cawthron Institute. She has represented New Zealand in cycling.