Data - Page 12

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.

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.

When nutrients accumulate in lakes (referred to as ‘nutrient enrichment’) above certain levels, they can make the lakes murky and green with algae, and lower oxygen levels. Lakes with extremely poor water quality are rarely suitable for recreation and provide poor habitats for aquatic species.

Percentile calculations for the following parameters are provided:
Trophic Level Index 3 (TLI)
Chlorophyll-a (CHLA)
Bottom-water dissolved oxygen (DObottom)
Ammoniacal nitrogen (NH4N)
Oxidised nitrogen (NO3N)
Total nitrogen (unfiltered) (TN)
Dissolved reactive phosphorus (DRP)
Total phosphorus (unfiltered) (TP)

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 "Lake water quality: Trophic Level Index" measure on the Environmental Indicators, Te taiao Aotearoa website.

When nutrients accumulate in lakes (referred to as ‘nutrient enrichment’) above certain levels, they can make the lakes murky and green with algae, and lower oxygen levels. Lakes with extremely poor water quality are rarely suitable for recreation and provide poor habitats for aquatic species.

Trends in the following parameters are provided:
Trophic Level Index 3 (TLI)
Chlorophyll-a (CHLA)
Bottom-water dissolved oxygen (DObottom)
Ammoniacal nitrogen (NH4N)
Oxidised nitrogen (NO3N)
Total nitrogen (unfiltered) (TN)
Dissolved reactive phosphorus (DRP)
Total phosphorus (unfiltered) (TP)

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 "Lake water quality: Trophic Level Index" measure on the Environmental Indicators, Te taiao Aotearoa website.

Fine sediment is the collective term for inorganic particles smaller than 2mm that are deposited on the beds of rivers and streams. Urban development, agriculture, and plantation forestry around waterways can increase the amount of sediment entering river systems. Sediment can clog the spaces between pebbles used by aquatic insects and fish, and degrade food sources and sites used for egg laying. Excessive sedimentation can also affect the suitability of rivers and streams for recreation.

Stream bed sediment observations are visual estimates of the proportion of the river bed covered by fine sediment. This information was collected during fish surveys, and stored in the Freshwater Fish database managed by NIWA. Observed in-stream sediment values for 10,025 sites are provided, dating from 1990 to 2011 in order to represent contemporary cover. The exception to this date range is the Fiordland area where all available information (1970 to 2011) was used to fill a representation gap.

This dataset relates to the "Stream bed sedimentation" measure on the Environmental Indicators, Te taiao Aotearoa website.

Fine sediment is the collective term for inorganic particles smaller than 2mm that are deposited on the beds of rivers and streams. Urban development, agriculture, and plantation forestry around waterways can increase the amount of sediment entering river systems. Sediment can clog the spaces between pebbles used by aquatic insects and fish, and degrade food sources and sites used for egg laying. Excessive sedimentation can also affect the suitability of rivers and streams for recreation.

Predictions of the proportion of deposited fine sediment cover are provided for every river reach in the River Environment Classification. These were calculated via a regression model using the measured proportion of fine sediment cover, slope of the river, climate and catchment land cover.

NZREACH = River location ID from the River Environment Classification
pred_obs = predicted contemporary percent fine sediment cover
pred_expec = predicted pre-human percent fine sediment cover

This dataset relates to the "Stream bed sedimentation" measure on the Environmental Indicators, Te taiao Aotearoa website.

Wetlands support unique biodiversity and provide important services. They clean water of excess nutrients and sediment, help absorb floodwaters, and act as carbon sinks (remove carbon dioxide from the atmosphere). They also have cultural importance for Māori, and provide valuable food and materials (eg flax). Draining wetlands for agricultural and urban development over the past 150 years has significantly reduced their extent, leading to a loss of biodiversity and natural function. This dataset contains estimates of the national extent of the different types of wetlands in contempary and pre-human times.

This dataset relates to the "Wetland extent" measure on the Environmental Indicators, Te taiao Aotearoa website.

Hydroelectricity is a renewable source of electricity. It makes an important contribution to New Zealand’s energy supply and economy.

This dataset relates to the "Contribution of hydroelectricity to total electricity generation" measure on the Environmental Indicators, Te taiao Aotearoa website.

Fresh water in New Zealand is highly valued for recreational activities, including fishing. Freshwater angling (primarily for introduced ‘sports fish’ such as brown trout, rainbow trout, and chinook salmon) is a popular leisure activity. Fish licences issued by Fish & Game New Zealand provide an indication of recreational fishing activity at freshwater locations around the country.

This dataset relates to the "Participation in recreational fishing" 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.