World Freshwater Data - Page 4

New Zealand has a diverse range of freshwater species. Many of these species are endemic to (only occur in, or only breed in) New Zealand. Freshwater fish and invertebrates are indicator species for the state of our freshwater environment. A decreasing population can indicate that the ecosystem is degrading.

This measure reports on the conservation status of New Zealand's indigenous freshwater fish and invertebrate species, including the number of species that have had a genuine change in conservation status between two monitoring periods (2009–13 and 2005–13). A change in a species’ conservation status reflects a change in its risk of extinction.

Freshwater fish are an important component of freshwater ecosystems, have intrinsic biodiversity values and are a valued resource for Māori, recreational and commercial fishers. The presence of fish species can be affected by changes in catchment land cover and land use, in-stream habitat, fish passages (routes for moving up and down waterways), pests, and contaminants.

File contains predicted capture, including upper and lower confidence intervals for 11 fish species, including indices of native fish, exotic fish, and all fish, over the period 1977 ̶ 2015.

Many of New Zealand’s iconic freshwater fish species are diadromous, which means they need to migrate between fresh water and the ocean to complete their life cycles. Some man-made structures such as culverts, weirs, stormwater pump stations, tide gates, and dams can obstruct diadromous fish migrations and prevent fish from reaching critical habitats.

This can result in the gradual decline and loss of fish species from some rivers, and streams and lakes. Protecting the connection between upstream and downstream habitats of our indigenous fish is as important as protecting their habitats themselves.

We do not yet have enough data to provide a national picture on fish barriers, so we report on known barriers to freshwater fish passage in the Hawke’s Bay region from culverts, weirs, and stormwater pump stations.

Submerged plants are good indicators of the ecological quality of lakes. Because they are attached to the bed of lakes, submerged plants are easy to observe and identify, and they are unable to move away from environmental changes. The plant species found within lakes can tell us about their level of habitat degradation and exotic weed invasion.

The file contains Lake submerged plant index scores for each sampling occasion.

Pesticides, which include insecticides, fungicides, herbicides and plant growth regulators, are commonly used in New Zealand to control insects, diseases and weeds in primary industries such as agricultural farming, forestry and horticulture. Once applied to land or crops, pesticides can make their way through soil and enter groundwater systems.

File contains whether a pesticide was detected at monitored wells, and if so, what the concentration is. File also includes surrounding land use, well use, well diameter, well depth, and screen depth, where available.

Groundwater quality indicators include E.coli, nitrate-nitrogen, ammoniacal nitrogen, and dissolved reactive phosphorus. Also included is data on pesticides, iron, manganese, electrical conductivity, and total dissolved solids. Information on sampling protocol, equipment, and method is provided.

Nitrogen occurs naturally in groundwater, but usually at very low concentrations. Agricultural and urban land use can add more nitrate-nitrogen to groundwater. If used for drinking water, high levels of nitrogen in groundwater can affect human health and the quality of surrounding rivers and lakes. Ammoniacal nitrogen is undesirable if groundwater is used for drinking, and elevated levels of nitrate and ammoniacal nitrogen can be toxic to fish and other animals. Surplus phosphorus drains (leaches) into groundwater as dissolved reactive phosphorus. It can also be present naturally from interactions between groundwater and rocks. Too much phosphorus can lead to excessive plant and algae growth where groundwater flows into surface water. E.coli in fresh water can indicate the presence of pathogens (disease-causing organisms) from animal or human faeces. The pathogens can cause illness for anyone who ingests them.

This dataset relates to trends in four groundwater quality indicators: nitrate nitrogen, ammoniacal nitrogen, dissolved reactive phosphorus, and E.coli. throughout New Zealand over the 10-year period 2005–2014.

River water quality is valued for many reasons including recreational value.
Escherichia coli (E.coli) can indicate the presence of pathogens (disease-causing organisms) from animal or human faeces, which can cause illness.

File contains the model outputs for E.coli concentrations as four different statistics for each river segment in New Zealand’s digital river network.

Groundwater quality indicators include E.coli, nitrate-nitrogen, ammoniacal nitrogen, and dissolved reactive phosphorus. Also included is data on pesticides, iron, manganese, electrical conductivity, and total dissolved solids. Information on sampling protocol, equipment, and method is provided.

Nitrogen occurs naturally in groundwater, but usually at very low concentrations. Agricultural and urban land use can add more nitrate-nitrogen to groundwater. If used for drinking water, high levels of nitrogen in groundwater can affect human health and the quality of surrounding rivers and lakes. Ammoniacal nitrogen is undesirable if groundwater is used for drinking, and elevated levels of nitrate and ammoniacal nitrogen can be toxic to fish and other animals. Surplus phosphorus drains (leaches) into groundwater as dissolved reactive phosphorus. It can also be present naturally from interactions between groundwater and rocks. Too much phosphorus can lead to excessive plant and algae growth where groundwater flows into surface water. E.coli in fresh water can indicate the presence of pathogens (disease-causing organisms) from animal or human faeces. The pathogens can cause illness for anyone who ingests them.

The file contains the raw data for all groundwater quality indicators. This dataset was used to calculate the percent exceedances of the drinking water standards for E.coli and nitrate-nitrogen over the period 2012–14.