River water quality percentiles, by monitoring site, 2009-2013
New Zealand's Environment Reporting Series: The Ministry for the Environment and Statistics New Zealand
River water quality water 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 ‘nuisance’ growths of river algae and aquatic plants, degrading habitat. High concentrations in the form of ammoniacal nitrogen and nitrate-nitrogen can be toxic to fish and other aquatic animals. 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 bacteria can indicate the presence of pathogens (disease-causing organisms) from animal or human faeces, which can cause illness. State (percentile) results for the following parameters, by monitored site for the period 2009-2013, are provided. Refer to Larned at al. 2015 for further details. * Clarity (CLAR), m * Ammoniacal nitrogen (NH4N), mg/m3 * Nitrate nitrogen (NO3N), mg/m3 * Total nitrogen (unfiltered) (TN), mg/m3 * Dissolved reactive phosphorus (DRP), mg/m3 * Total phosphorus (unfiltered) (TP), mg/m3 * Escherichia coli(ECOLI), n/100 mL 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 https://data.mfe.govt.nz/x/54W4dX from the Ministry for the Environment dataservice. This dataset relates to the "River water quality" measures on the Environmental Indicators, Te taiao Aotearoa website.
National Institute of Water and Atmospheric Research; all regional councils