Adapted by Ministry for the Environment and Statistics New Zealand to provide for environmental reporting transparency. Dataset used to develop the “River water quality: Nitrogen” indicator, (available at River water quality: nitrogen | Stats NZ ).
Nitrogen in river waters is one of five parameters that provide an overview of New Zealand’s River water quality and how it is changing over time. Nitrogen is an essential nutrient for plants and algae. Some nutrient supply is a natural component of healthy rivers, but agricultural and urban land use, and infrastructure such as wastewater treatment plants, can add more nitrogen to waterways. Too much nitrogen can lead to excessive growth of algae, which can deteriorate river habitats. In very high concentrations, some forms of nitrogen, including nitrate-nitrogen and ammoniacal nitrogen, can be toxic to aquatic life.
This dataset shows:
concentrations of total nitrogen (TN), nitrate-nitrite-nitrogen (NNN) and ammoniacal nitrogen (NH4N) measured at monitored sites, expressed as percentiles for the period 2016–2020
a comparison of measured nitrate-nitrite-nitrogen and ammoniacal nitrogen concentrations at monitored sites with the proportion of human modified landcover in the upstream catchment area
how measured median values compare to the default guideline values in the Australian and New Zealand guidelines for fresh and marine water quality (ANZG, 2018), which indicates the risk of environmental impairment
toxicity to aquatic species, as defined by the National Objectives Framework (NOF) bands related to ecosystem health (MfE, 2020)
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 https://environment.govt.nz/publications/environment-aotearoa-2022/.