Freshwater Tables - Page 4

Benthic macroinvertebrates are small animals without backbones (eg insects and worms). They live on and under submerged logs, rocks, and aquatic plants on the beds of rivers and streams during some part of their life cycle. Macroinvertebrates play a central role in stream ecosystems by feeding on periphyton (algae), macrophytes (aquatic plants), dead leaves and wood, or on each other. A high macroinvertebrate community index (MCI) indicates a high level of river health.

File contains trend statistics and calculation results for the period 2004-2013.

For more information please see:
Larned, S, Snelder, T, Unwin, M, McBride, G, Verburg, P, McMillan, H (2015).Analysis of Water Quality in New Zealand lakes and Rivers: data sources, data sets, assumptions, limitations, methods and results. NIWA Client Report no. CHC2015-033. Available at data.mfe.govt.nz/x/DDui3u from the Ministry for the Environment dataservice.

This dataset relates to the "River water quality: Benthic macroinvertebrates" measure on the Environmental Indicators, Te taiao Aotearoa website.

Freshwater fish are an important component of freshwater ecosystems and a valued resource for Māori and recreational fishers. The community of fish species found at a site 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. The fish index of biotic integrity (IBI) is a measure of the condition of fish communities at sites across the country.

This dataset relates to the "Freshwater fish communities" measure on the Environmental Indicators, Te taiao Aotearoa website.

Freshwater fish are an important component of freshwater ecosystems and a valued resource for Māori and recreational fishers. The community of fish species found at a site 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. The fish index of biotic integrity (IBI) is a measure of the condition of fish communities at sites across the country.

This dataset relates to the "Freshwater fish communities" measure on the Environmental Indicators, Te taiao Aotearoa website.

This indicator reports on six measures of lake water quality based on spatially modelled data for:

• chlorophyll-a
• total nitrogen
• ammoniacal nitrogen
• total phosphorus
• water clarity
• trophic level index (TLI3).

​

For these measures we report on:

• modelled median values for the period 2013–17
• for selected measures, how these values compare to the National Objectives Framework (NOF) bands related to ecosystem health (MfE, 2017).

​

This indicator includes spatial predictions for 3,802 of 3,820 lakes in New Zealand (majority of New Zealand lakes that are larger than 1 hectare), based on measurements at 61–104 lake sites (the number of sites differs by measure).

More information on this dataset and how it relates to our environmental reporting indicators and topics can be found in the attached data quality pdf.

River flow is the quantity of water passing a point over a certain time. Each river or stream has its own natural flow characteristics, such as peak flows following rain or high spring flows from snow melt. Overall, this affects how much water is available for irrigation, drinking water, hydroelectricity generation, and recreational activities. River flows also influence a waterway’s physical form, habitat, and ecological processes like migration, spawning, and food supply for aquatic life.

This dataset relates to the "The geographic pattern of river flows" measure on the Environmental Indicators, Te taiao Aotearoa website.

We report on trends in nitrate-nitrogen from livestock that has leached from soil per year across New Zealand since 1990.

Nitrogen is an essential nutrient for plant growth. It occurs naturally, but in agricultural systems more nitrogen is commonly added to soils as fertiliser or as urine or dung from livestock. Not all the additional nitrogen can be used by plants and microorganisms, so some nitrate-nitrogen may leach (drain) from the soil. Livestock urine is the dominant source of nitrate-nitrogen leached from soil. Leached nitrate-nitrogen can enter groundwater and waterways, potentially causing ecological harm. The amount of nitrate-nitrogen leaching from the soil varies around the country as a result of different land uses, climates, and soils.

More information on this dataset and how it relates to our environmental reporting indicators and topics can be found in the attached data quality pdf.

Summary report available at www.mfe.govt.nz/publications/fresh-water/spatial-n...

Nitrogen is an essential nutrient for plant growth. It occurs naturally in the environment but is added in agricultural processes (typically as fertiliser) to boost production. Although much of the applied nitrogen is taken up by plants, livestock waste returns a considerable amount to the soil. Nitrate formed from this waste easily drains (leaches) from the soil before plants can absorb it, and it can enter waterways, potentially harming ecosystems.

This dataset relates to the "Trends in nitrogen leaching from agricultural activities" measure on the Environmental Indicators, Te taiao Aotearoa website.

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.

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.

River water quality is valued for many reasons including ecological function and habitat, recreational value, its role in supporting people and industry, and its cultural significance. Nutrients such as nitrogen and phosphorus are essential for plant growth, however too much in rivers can lead to excessive growth of river algae, which can degrade habitat.

High concentrations of nitrogen in the form of ammoniacal nitrogen and nitrate-nitrogen can be toxic to fish and other aquatic animals, and nitrate-nitrogen can be toxic to humans. Water clarity is a measure of underwater visibility, and affects habitat of aquatic life such as fish and birds, and can also impact on aesthetic values and recreational use of rivers and streams. 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 river water quality indicators as medians for each river segment in New Zealand’s digital river network.