Fresh water is often taken for granted.
Clean water is one of Northland's most scarce resources. Despite our high rainfall compared with other parts of the country, the small area of land means most rainfall drains away to the rivers and the sea. The rivers we have are short and slow moving. Near the coast they are often heavily influenced by ocean tides.
All living things need water to survive and clean water is important for the survival of us all.
The average New Zealander uses between 250 and 300 litres of water per person per day.
Water uses include:
- Cooking, drinking and hand washing uses 25 litres per person.
- Bathing, 80 litres per person
- Showers, 30 litres per person
- Toilet, 3-9 litres per flush (dual flush)
- Automatic washing machine, 49-100 litres per wash (depending on the efficiency of the machine)
- Dishwasher, up to 35 litres per wash
- Dripping tap can waste up to 3640 litres per year (more than a bath full each week)
- A hose or garden sprinkler can use between 1000 and 2000 litres per hour.
Northland Regional Council's role and policies
Under the Resource Management Act 1991, the Northland Regional Council's (NRC) key role is to promote the sustainable management of Northland's water resources. This requires water to be available for people to provide for their wellbeing. This needs to be done in a way that is not at the expense of future generations or its life-supporting capacity or by causing any significant harmful effects.
The Council controls the taking, use, damming and diversion of water. It controls activities and discharges that affect the quality, level and flow of water in water bodies, and the discharge of contaminants into water. Many of these activities need a Resource Consent, and consideration is given to the Council's Regional Plans and Regional Policy Statement before applications are granted.
The Regional Water and Soil Plan for Northland identifies the significant water and soil issues so that these resources can be sustainably managed. There are rules in the plan to cover all sorts of activities involving discharges, taking or use of water and land disturbance. Many activities with minor effects don't need a resource consent while others do or are prohibited.
The Regional River Water Quality Monitoring Network has been operating since 1996. The network provides information about river water quality in the Northland region so that baseline levels and water quality trends can be monitored.
What is water and why do we need it?
Water is needed by all living things to survive. It is a colourless, transparent, tasteless and odourless compound of oxygen and hydrogen in a liquid state. In fact, humans contain large amounts of water. Water continually circulates from the oceans to the atmosphere to the land and back to the oceans. This complex process is known as the water cycle. It keeps a balance between water in the oceans, water on the land and water in the atmosphere.
The water cycle
Diagram of the water cycle.
Fresh water resources
Northland's fresh water resources include rivers and streams, lakes, wetlands, springs, groundwater (aquifers) and dams. See Rivers and Streams information pack.
Fresh water is used in many ways.
Domestic: A large proportion of domestic water is drawn from groundwater, most of it untreated.
Agriculture and horticulture: Farmers and orchardists need large amounts of water for irrigation, stock water supply and cowshed milking process and cleaning.
Urban: Cities and towns use fresh water for drinking water and sewage disposal. Most urban areas have piped water supplies, often fed from large dams. Water undergoes a treatment process to make it safe for humans to drink.
Industrial and commercial use: Big factories such as meat works need large quantities of water for their processing.
Dams: These can range from small farm dams for stockwater and irrigation to dams for irrigation and recreation.
Recreation and tourism: Water-based adventure tourism such as white water rafting and eco tours are popular in many parts of New Zealand. Holidaymakers enjoy water skiing on fresh water lakes. Swimming, rafting, yachting, kayaking and windsurfing are all popular water activities in Northland.
Aquaculture: Fish farms are another use of fresh water, although not common in Northland.
Māori: Water has cultural value to Māori as a lifegiving force and is a habitat for important food sources.
Influences on water quality
A wide range of factors - most of which result from human activities - have an influence on water quality.
Sediment from eroded banks makes water muddy
It's a case of looking upstream at all the different inputs that affect the quality of water downstream. There is a strong relationship between land use and the water quality of streams, rivers and groundwater. The greatest area of intensive land use is in the lowland area where the river gradient lessens and water slows down. Northland's lowland water quality is generally poor.
The business of growing trees involves major disturbance to soils, especially when harvesting and planting the next crop. At this time, the earthworks needed to clear the land for planting can result in a lot of silt ending up in rivers and streams. Forestry is a major industry in Northland, with thousands of hectares being changed from farmland into forestry blocks. Trees are harvested every 25-35 years, which means for most of the time the trees are growing and there is little disturbance to the land. Forestry also intercepts water that would normally recharge groundwater systems. Forestry operators are required to form sediment traps to prevent silt muddying the water in streams. They are also required to leave a barrier of usually native bush when harvesting to help filter sediment and keep it out of waterways.
Cows in water cause pollution and erosion of streamsides. Another major industry in Northland is farming, which can have a major effect on water quality in nearby streams, rivers and groundwater. While improvements have been made, farming practices still affect water quality through runoff from chemicals and fertilisers, dairy shed effluent, silage pits and races. Over many years, farmers have been encouraged to upgrade their dairy shed effluent treatment systems to reduce contamination of streams. This is helping clean up Northland's water sources.
Cities, towns and other settlements have a major effect on water quality because of the sheer number of people living there. Kerbing and stormwater outlets collect water that runs along streets, down the drains and into the rivers and sea.
Everything that is thrown on the roadside can end up in the stormwater system and be washed into streams to affect water quality. Pollution can also filter through the ground into groundwater.
Drains should only drain rain.
Cars and trucks on the road or parked in car parks can drip oil and fuel in small amounts. When it rains these oil drips are washed into the stormwater drains. People cleaning their cars often allow the suds from their washing liquid to wash into the drains. Some people even throw left-over paint or engine oil down drains without thinking about where this poisonous brew will end up.
While each single incident may seem a small amount of waste, the sheer number of people living in cities combines to create a major effect on water quality. Wrappers from fast food outlets are one of the major sources of litter in city streets, all of which can be washed down into drains.
Remember: "Drains should only drain rain.''
Have a look around your city, town or roadside. See what you can find waiting to pollute waterways.
Sewerage systems and rubbish dumps are also factors in water quality. Large populations put pressure on the ability of systems to dispose of waste without affecting the environment. The Whangarei District Council uses wetlands to help filter and purify waste water. This acts as a buffer zone between the treatment station and the Hatea River downstream.
Industrial development: Factories and businesses produce different types of waste as byproducts in their processing. Discharges might be fumes. These can rise up into the atmosphere causing pollution that is then brought down to earth again in raindrops to affect water quality in rivers and the sea. Trace metals as byproducts of manufacturing processes and fuel and oil dripping from trucks and machines can all enter water bodies as runoff from rain. Dust and fertiliser particles can affect water quality near fertiliser works. The Northland Regional Council keeps a check on businesses where waste is produced, and requires them to adhere to Resource Consents conditions when they operate. The effect on the environment is one of the main considerations in granting a Resource Consent.
Large factories put pressure on the surrounding environment.
Businesses are encouraged to consider how to reduce waste from creation of their products through to the disposal of those products, when they are no longer useful to their customers.
Horticulture: Like farming, growing crops and trees on land can have an effect on water quality. Many horticulturists use pesticides and herbicides to keep insects and diseases from harming their crops. These chemicals end up in the soil and run-off, which can end up in groundwater and streams. Horticulturists are encouraged to use as few chemicals as possible and organic farming is gaining in popularity as people consider how to reduce contamination of land and water.
Geology and soils: The character of rivers, streams and groundwater reflects the terrain they run through. The types of rock the river travels through upstream influence the mineral content of the water. For example, a river travelling through greywacke rock will contain a lot of iron.
The Mangakāhia River.
The speed at which the water flows affects water quality too. Fast-moving water stays cooler and has a lot of dissolved oxygen from the turbulence of crashing over rocks and water falls. Slow-moving water tends to be heated by the sun, and the increased water temperature can make it more susceptible to algal blooms. Northland rivers tend to be short, slow moving, and heavily influenced by tides downstream where they reach the ocean.
Native bush: Water flowing through native bush may seem clear, but it is not necessarily so. The decomposition of leaves dropped from trees all affects water quality.
Micro-organisms also can be a danger to people and animals. The large number of trampers using our bush - some of whom are from overseas - have left their mark on water quality by accidentally introducing bugs to waterways. These include giardia, which can leave people ill for months with stomach pains and diarrhoea. It is now thought that possums have picked up these bugs and have spread them throughout Northland waterways. Water from streams should always be boiled for at least 10 minutes to kill any tiny bugs that might make you sick.
Physical issues: Water quality is affected by physical issues such as the temperature of water, the amount of dissolved oxygen and the amount of vegetation shading waterways.
Riparian strips are areas of trees and plants alongside streamsides. These have to be of enough width to help filter and reduce the amount of runoff from pastures. The shading from trees helps reduce water temperature by cutting the amount of sunlight reaching the stream water. Algae needs sunlight, warmth and nutrients to be able to grow.
Rivers and streams
Northland has a dense network of rivers and streams. None of them are considered major on a national scale. Northland's narrow land mass means most of our rivers are relatively short with small catchments. Most of the major rivers have their outlets into harbours, with only a few discharging directly to the coast. The Northern Wairoa River is Northland's largest river, draining a catchment area of 3650 square kilometres, or 29 percent of Northland's land area. The Northern Wairoa is tidal for about 100 km. See the Rivers and Streams Information Pack for more information about rivers and streams in Northland.
Northland has a large number of small, shallow lakes and associated wetlands. Most of these have been formed between stabilised sand dunes on the west coast. These dune lakes are grouped on the Aupouri, Karikari and Pouto peninsulas. Most are between five and 35 hectares in area and are generally less than 15 metres deep. Lake Taharoa of the Kai Iwi group near Dargaville is one of the largest and deepest dune lakes in New Zealand. It covers an area of 237 hectares and is 37 metres deep.
Lake Omapere showing extensive areas of oxygen weed reaching the surface.
Lakes are different from rivers in that they may have little or no outlet so any pollution tends to stay in the water body. The large pooled mass of water is more susceptible to heating by the sun, encouraging plant growth and making weed overgrowth and algal blooms more likely. Some algal blooms can be poisonous to animals and humans - as the 1985 bloom in Northland's largest lake, Lake Omapere, proved to be. Lake Omapere is susceptible to algal blooms because although it is large - covering 1200 ha - it is shallow at two metres deep.
The 1985 algal bloom polluted the lake as well as the Utakura River and the upper reaches of the Hokianga River. There were three algae involved, all blue-green algae that are potentially toxic to animals and humans. Within the lake the algal bloom formed scum that was 1-2cm thick in places, and there was a massive decline in water clarity and quality over the whole 1200ha lake. The bloom made the water smell bad, and posed such a health problem that the Northland Area Health Board stepped in to ban the Kaikohe Borough Council from extracting public supply water from the lake.
Farmers around the lake reported that stock refused to drink the water. During the summer, the swan population decreased and nesting in January 1986 was abandoned.
Downstream of the lake there were major disruptions because farmers and the Maori community could not use the river for water or swimming. The four marae in the area relied on the river to supplement their domestic roof and spring water during most summers. Marae functions over the 1985-86 summer had to be held out of the district. Fish and shellfish in upper reaches of the Hokianga Harbour became unsafe to eat.
Efforts are being made to introduce grass carp to eat oxygen weed in the lake, and reduce the chance of the lake collapsing again to create conditions ideal for another toxic algal bloom. Representations have been made to the Government to get more help with funding. The NRC is continuing to monitor lake water quality and algae, and has contracted NIWA to assist in the monitoring of weed abundance.
Groundwater is water under the ground, which collects in water bodies called aquifers. Aquifers are filled by water that is filtered through soil and rock. Many aquifers are used as water sources by land owners through bores and wells.
Groundwater can be contaminated in a number of ways by leaks from septic tanks, underground fuel tanks and pipes, landfills, mines, timber treatment leachate, chemical spills and offal holes.
More general contamination can come from landowners using pesticides and fertiliser which can gradually filter down through the soil and into the aquifer.
NRC land management officer Doug Foster checks an aquifer near Kaitaia through a pipe.
Salt water can contaminate aquifers if excess water is drawn from coastal bores. When the fresh water level in the aquifer falls too far, the salt water can seep in to replace it.
The area around the top of a well needs to be sealed properly so that aquifers are not contaminated through the hole or down the side of pipes. Chemicals should not be stored or sprayed near the well opening, animals should not be able to fall down it and surface water should not be able to drain into the well.
The well hole should never be used as a dumping ground even when it is no longer in use at the risk of contaminating the underground water supply for other users.
Underground water should not be allowed to bubble up from the ground through unsealed bores because of the waste of water, drop in underground pressure and risk of contamination. Groundwater contamination affects human and animal health, as well as impacting on crops and aquatic ecosystems. See the Rivers and Streams information pack.
Checking it out
There are many clues to water quality, building up a picture of the overall health of a stream. Clues to look for include insects, aquatic plants, algae, rooted plants, water clarity and colour.
There are certain types of insects, invertebrates and fish that have a low tolerance of pollution. If they are present in good numbers, it can indicate a healthy stream.
While people often judge the health of a stream by how it looks, this can be very misleading. Clear streams can still contain many contaminants.
Former NRC hydrologist Dale Hansen collects data from a Northland stream near Kaitaia straight into his laptop computer. The probe in the water can measure conductivity, pH, dissolved oxygen and temperatureThe pH scale
The acidity or alkinity of water is measured using the pH scale. The measurement uses the numbers 0 to 14 to indicate the degree of acidity or alkalinity of water. Creatures in Northland streams are generally comfortable living with pH readings between 6.5 and 9. Beyond that they will move away or die. On the scale, 0 is very strong acid, and 14 is very strong alkaline. Pure water is neutral, scoring 7 which is the middle of the pH scale. Vinegar has a pH level of 3, and lemon juice has a pH of 2. They are both acidic.
Oxygen is important in water because fish and aquatic life use it to breathe. Water naturally contains some dissolved oxygen, the amount varying depending on the temperature of the water. When pollution such as sewage or rotting vegetation is present, bacteria breaks down the organic matter using oxygen in the process. Too little oxygen left in the water means fish will not have enough to live there and they may die. Waterfalls and rapids help put air back into the water.
Other biochemical tests are conducted for conductivity, temperature, faecal coliforms, enterococci, total phosphorous, dissolved reactive phosphorous, nitrite and nitrate nitrogen, ammoniacal nitrogen, nutrient status, turbidity and absorption and water clarity.
These chemical tests all help to build a picture of what is happening in the water.
Former NRC monitoring officer Barry McIntosh with water samples ready for testing. He is comparing a muddy sample with a clear one.Creatures:
Water can be classified in many ways. By observing the numbers and species of micro-organisms and invertebrates (creepy crawlies) in a water sample, an impression can be gained of the water quality.
Water that is rich in nutrients is called eutrophic. Water with few nutrients is called oligotrophic.
Eutrophic water is considered polluted when it supports a large population of micro-organisms. These organisms use the nutrients as a food source and can multiply rapidly. Large numbers can have a detrimental effect on the quality of a harbour, lake or river.
Anaboena - one of the micro-organisms that can be found in water.
Algae: Algae are tiny plants. They are chlorophyll-bearing and can comprise one cell or many cells. Some float in the water while others attach themselves to rocks or other formations underwater. Algae present in large numbers become an algal bloom which can sometimes be poisonous to people and animals.
Protozoa: These include flagellates, ciliates, amoeba and sporozoa (parasites). Some feed on algae, some on bacteria and some live on other protozoans. Many form cysts and can be airborne and dispersed when a water body dries up. An example of a type of protozoa is giardia which causes a nasty illness in people and is present in many Northland streams.
A water sample is collected. Testing can help trace the source of contamination. Invertebrates: Two most common groups of these are rotifers and nematodes. Rotifers get their name from the fact that they look like a pair of rotating wheels when they move. Nematodes are worms, usually less than 1cm long. An example of worms is the roundworm, which can infect animals.
Larger invertebrates can be seen living in streams - try turning over rocks and looking carefully. Some larger invertebrates such as the mayfly are very sensitive to pollution. Large numbers of mayflies indicate good water quality.
Northland is subject to a variety of hazards, which affect people, property and the environment. Flooding is the most common hazard - several of the region's major settlements, as well as important farming areas, are located within flood plains. Other emergencies could include pollution, such as when a milk tanker crashes and spills its load or a factory accidentally discharges chemicals into a stream.
The Northland Regional Council keeps a constant check on water levels around Northland through data gathered at 37 water monitoring stations, many of which are on rivers.
While flooding does have a sudden and major effect on water quality, especially when there is a lot of sediment washed into streams and rivers, nature can recover quite quickly from these natural events.
NRC monitoring staff take water samples regularly to keep an eye on the general state of the environment. Monitoring staff also check water quality to ensure industries are keeping to their consent conditions. They will take samples if there are any suspicions of pollution or other problems.
If there was a spill of chemicals or milk into a stream, staff would use their monitoring equipment to try and trace the source of the spill and monitor its effect on the surrounding environment.
The NRC operates a "traffic light system" for water quality to show levels of safety at monitoring sites. Green indicates an area is considered safe for bathing, amber indicates there could be potential health risks and red indicates bathing should be stopped and warning signs should be erected. The risks are calculated by testing for bacteria in the water.
Importance to Māori
To Māori, water is an essential ingredient, regarded as a taonga or treasure. It must be safeguarded for future generations. Water is considered to possess a life force, mauri, and have a spirit, a wairua. To Māori, any discharge of contaminants into water, no matter how well purified in a treatment process, reduces the water's ability to sustain life. It thereby reduces its mauri, or life force.
Waitangi Tribunal cases provide guidance on the importance of water to Māori including five principles.-
- Fresh water is a lifegiving gift
- The Māori conception of rivers is holistic
- It is irrelevant to consider whether waste can be treated to be "pure" before discharge into rivers.
- Only Tāngata Whenua can determine the spiritual and cultural significance of a river resource to Māori.
- Environmental consultation with iwi is a Council duty under the Resource Management Act.
It is important to Māori that water remains pure and uncontaminated in order to continue to protect, preserve and sustain life for future generations. Wai is the Māori word for water, and many New Zealand place names feature it as part of the place name, giving a clue to its meaning.
Water is given different terms by Maori according to its status.
Waiora is water in its purest form, usually rainwater caught before it touches the earth. This water is used for ritual purposes.
Wai Māori is fresh water or drinking water from springs. It can be used for everyday purposes.
Waimate or Waikura is water that is stagnant or polluted and is no longer capable of sustaining life.
The NRC works with the community to protect our fresh water resources by having rules for people and businesses. The Council emphasises education to help explain these rules. In some cases these rules are enforced under the Resource Management Act. Plans and policies are set in place to manage the water resource with the aim of improving water quality for future generations.
Fencing this bank from stock would help to stabilise the edges.
Farmers have been urged to set up proper effluent ponds with some degree of treatment. They are being encouraged to stop discharging any effluent in creeks.
Landowners are encouraged to fence off streams from stock. Animals damage stream banks by walking on them - causing erosion - and also pollute water with their effluent. However, farmers are then forced to provide other sources of water for cattle, and all that comes at a cost.
The NRC sets standards for sewage and water treatment systems to make sure they meet acceptable health standards. If septic tanks are not working properly, there can be low level seepage all year, which can become worse after storms.
What can you do?
Stream Monitoring with SHMAK kits
Students monitoring stream health.
The New Zealand Stream Health Monitoring and Assessment Kit (SHMAK for short) allows us to measure stream health. The kit has been designed to be simple to use and measures important factors of a stream such as the temperature of water, velocity, pH levels and creatures living in the stream.
Regular monitoring allows us to build up a record, and the information can be plotted on a graph to give an impression of how stream health is changing over time.
The kits contain a manual with monitoring forms, full instructions and background information. There are coloured identification guides for bugs and slime, and a set of monitoring equipment including water clarity measuring tube, conductivity meter, pH papers, thermometer, sample container and magnifier.
The kits have been developed by the National Institute of Water and Atmospheric Research (NIWA) in partnership with Federated Farmers of New Zealand. They are being promoted for use by the New Zealand Landcare Trust. The projects have been partly funded by the Ministry for the Environment's Sustainable Management Fund.
SHMAK kits cost $375 plus gst and are available from NIWA Instrument Systems, PO Box 8602, Christchurch.
NRC staff and the Landcare Trust can help with advice on using the kits.
Check under rocks to see what lives there and use the SHMAK kit charts to identify them.
Adopt a stream near your school and undertake water monitoring. Remove any litter, and find out what types of industry upstream may be affecting the water quality.
Support tree-planting efforts, and discourage any of your friends or family from littering or pouring anything down drains.
- Adopt a tap in your household and make sure it is never left dripping. Dripping taps waste a lot of water.
- Turn off the tap while brushing your teeth.
- Quickly repair dripping taps or leaking pipes
- Consider low-flush toilet options to save water.
- Wait until your dishwasher is full before using it.
- Clean drives and paths with a broom instead of a hose.
- Water the garden at cooler times of the day to reduce evaporation.
- Collect rainwater from the roof to water the garden.
When hunting, fishing, tramping or boating:
- Keep soap, detergent and toothpaste out or streams and lakes. Use a bowl or cup.
- Fillet fish away from the water's edge
- Use toilets provided, or dig a shallow pit at least 10 metres from the river or stream.
NRC staff; Well water pamphlet, Canterbury Regional Council; A Microscopic View on Water Quality; Water The Essence of Life pamphlet, Whangarei District Council; Stream Monitoring with SHMAK pamphlet, Federated Farmers and NZ Landcare Trust; Fresh Waters of Canterbury pamphlet, Canterbury Regional Council; Lake Omapere submission, Rio+10 Community Programme information pack. Document date: June 2001