Know your catchment – Engage and learn about freshwater in the Waitaki catchment

Water is so important to New Zealand: its people, animals, and our cultural wellbeing. It is important we become educated about it and look after it so it is healthy now and for generations to come.

Know Your Catchment is a platform for the community to engage and learn about freshwater in the Waitaki catchment, which is in North Otago and South Canterbury, on the east coast of the South Island of New Zealand. The water monitoring data include information about water quality, irrigation, wetlands, recreation, and different ways freshwater supports wellbeing.

On this platform you will find:

water quality data and trends for groundwater and surface water across South Canterbury and North Otago
links to river flows and lake levels, and
information and stories about sites of interest.

Navigating Know Your Catchment is easy, simply follow these video instructions to find out more about one of New Zealand’s most valued resources, water!

Algal bloom	Dense, prolific growths of algae which often make water discoloured and turbid (murky) and can create scum on the water’s surface. Some algal blooms can be toxic to humans and animals.
Aquifer	An underground “lake” of groundwater. An aquifer can be “confined” (surrounded on all sides by solid rock), “unconfined” (surrounded by, or within, gravels and stones that allow water to pass through), or a mixture of the two, “semi-confined.” Aquifers can be very shallow (a couple of metres underground) or very deep (hundreds of metres underground) or anywhere in between. Water in aquifers can move quickly or very slowly – the water in some aquifers is thousands of years old.
Catchment	The area of land draining into a river, basin, reservoir, or lake (see also watershed).
Dissolved oxygen	The oxygen content of water. Dissolved oxygen is important for fish and other aquatic life to breathe – generally, the higher the better. For example, water quality guidelines recommend that water should be more than 80 percent saturated with dissolved oxygen for aquatic plants and animals to be able to live in it.
E. coli	Water found beneath the ground surface. When it rains, some of the rainwater soaks into the soil and moves downward into the ground, fillings cracks and spaces in rock and gravel. Once the spaces get completely saturated, an aquifer may form (see above). When we dig or drill a well, we can intercept some of that water and pump it out of the ground to use for drinking water supply or irrigation.
Nitrogen (and its various forms)	A common chemical element, which can take several forms and is highly soluble (easily dissolved) in water. Nitrate-nitrogen is a molecule made up of nitrogen and oxygen with the chemical formula NO3. Nitrate is a very important plant nutrient but because it is highly water soluble, it leaches through soils and into groundwater very easily, particularly after heavy rainfall. It is one of the most common contaminants of rivers, streams, and groundwater in rural and urban areas. Sources include excessive application of some types of fertiliser, and animal and human waste. On grazed pastures, animal urine patches can be a major source of nitrate leaching. Nitrite-nitrogen is a molecule with the chemical formula NO2. Concentrations of nitrite are normally low compared to nitrate and ammoniacal nitrogen. However, too much nitrite can be toxic in drinking water to humans and livestock. Ammoniacal nitrogen is the concentration of nitrogen present as either ammonia (NH3) or ammonium (NH4). Ammoniacal nitrogen can be transformed to other forms of nitrogen and are very important plant fertilisers. Ammoniacal forms of nitrogen enter waterways mainly through point source discharges, such as raw sewage, dairy shed effluent, or when animals poo and wee directly into waterways. It is toxic to aquatic life at high concentrations. Total Nitrogen (TN) is the sum of all organic and inorganic forms of nitrogen found in a water sample added together (i.e., nitrate-nitrogen, nitrite-nitrogen, ammoniacal-nitrogen, and organic nitrogen such as amino acids or plant tissue). Why is too much nitrogen a problem? Too much nitrogen can contribute to rapid growth of aquatic weeds and algae in rivers, streams, lakes, estuaries, and the ocean. This can result in plant or algal blooms. As the plants die and decompose, oxygen in the surrounding water is used up and in severe cases this reduction of oxygen kill aquatic life. Nitrogen itself can also become toxic to aquatic life at high concentrations, particularly under certain temperature and pH conditions. In drinking water, the nitrate form of nitrogen can be toxic to humans and other animals at high concentrations (see the discussion on nitrate above).
Non-point-source pollution	Pollution which does not come from a single ‘end-of-pipe’ source, but from many small sources, or from a wide area such as leaching through soil, overland run-off, or erosion. Also known as diffuse pollution.
Nutrient	A substance, element, or compound that nourishes organisms and helps them grow. In relation to water management, excessive nutrient-enrichment (in combination with other environmental factors, such as water temperature) can lead to excessive growth of algae or aquatic weeds.
Nutrient management	The active management of nutrient inputs and outputs in farm systems.
Pathogen	A disease-causing agent.
Phosphorous	A chemical element, the most common form of which is only slightly dissolvable in water. This means it clings to soil and enters surface waterways through erosion and sediment in overland run-off. Dissolved reactive phosphorous (DRP) is a measure of the dissolved (soluble) phosphorus compounds that are readily available for use by plants and algae. Because of this, high concentrations of DRP can lead to nuisance algal or plant growths (blooms). Total phosphorus (TP) is a measure of all the types phosphorus present. It includes the phosphate that is stuck to soil (sediment) as well as dissolved reactive phosphorus (DRP) which is more readily available for plants. TP is an important measure because most phosphate enters our rivers attached to sediment via run-off.
Point-source pollution	Pollution which comes from a single ‘end-of-pipe’ source.
Riparian	Relating to the bank or margin of a river, stream, or wetland.
Suspended solids	Total suspended solids (TSS) is the measure of suspended particles in water that are not dissolved. The more solids, the murkier the water. Poor water clarity can have many adverse effects on stream and lake ecosystems. Murky water can make the water unsuitable for drinking by livestock and unsafe or unpleasant for swimming. High sediment can also harm aquatic life by clogging their gills which reduces their ability to take up oxygen. As fine particles settle in slower-moving downstream areas, the spaces between rocks and gravel are filled making the bottom habitat unsuitable for fish and other aquatic species. Poor water clarity will also affect the amount of light reaching the river bottom, potentially limiting plant growth. Some waterways have naturally turbid water, such as those that run off glaciers.
Watershed	The geographical boundary between adjacent drainage areas (see also catchment).