River water quality: Nitrogen, flow adjusted trends, 1991 - 2020

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:

trends in concentrations of total nitrogen, nitrate-nitrite-nitrogen, and ammoniacal nitrogen based on measurements made at monitoring sites during the 10-year period from 2011 to 2020, the 20-year period from 2001 to 2020, and the 30-year period from 1991 to 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/.