National River Water Quality Network
The National River Water Quality Network includes 77 sites located on 35 rivers throughout New Zealand. There are 44 North Island and 33 South Island sites on rivers which drain about half of New Zealand's land area. The network is operated by the National Institute of Water and Atmospheric Research (NIWA).
These sites have been sampled monthly since 1989 for a range of water quality variables, such as:
Periphyton (algae which grows on the river bed) is also visually assessed each month at most of the national network sites.
Monitoring of macroinvertebrates (small aquatic animals) is carried out annually at 66 of these 77 national sites.
The sites in the national network have been ranked based on nutrient levels, water clarity, bacterial levels, macroinvertebrates and periphyton. The results are presented in river water quality league tables.
For more information please see recent reporting on water quality trends and trends in periphyton cover at national network sites.
Monitoring sites in the National River Water Quality Network
Source: National Institute of Water and Atmospheric Research.
Site types
The 77 sites in the network have been classified, depending on the degree of impact on them, into three categories:
- baseline (22 sites)
- pseudo-baseline (10 sites)
- impact (45 sites).
'Baseline' sites are likely to have no or little diffuse or point source pollution and should therefore be near-natural. 'Pseudo-baseline' sites are the best available baseline sites for a catchment or area and are likely to be lightly impacted (eg, by low intensity pastoral farming). 'Impact' sites are downstream of areas of agriculture, forestation, industry and urbanisation.
This information has come from the latest state of the environment report Environment New Zealand 2007 and the National River Water Quality Network which is operated by NIWA with funding from the Foundation for Research, Science and Technology.
You can access the national network data for 2007, as well as more site information, in this spreadsheet.
You can access the results of trend analysis on the national network data from 1989 to 2007 in this spreadsheet.
Last updated: 10 August 2009
