River water quality: Phosphorus, state, 2016 - 2020

River water quality: Phosphorus, state, 2016 - 2020

2022-07-20

Adapted by Ministry for the Environment and Statistics New Zealand to provide for environmental reporting transparency. Dataset used to develop the "River water quality: phosphorus" indicator (available at https://www.stats.govt.nz/indicators/river-water-quality-phosphorus).

Phosphorus 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. Phosphorus is an essential nutrient for plants and is a natural component of healthy rivers. Agricultural and urban land use, and infrastructure such as wastewater treatments plants, can add more phosphorus to waterways, which can increase algae growth and biomass. This in turn causes deterioration of river habitats.

This dataset includes:

concentrations of total phosphorus (TP) and dissolved reactive phosphorus (DRP) measured at monitored sites, expressed as percentiles for the period of 2016–2020

a comparison of measured total phosphorus and dissolved reactive phosphorus concentrations at monitored sites with the proportion of human modified landcover in the upstream catchment area

how measured median total phosphorus and dissolved reactive phosphorus concentrations 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

measured dissolved reactive phosphorus concentrations compared to 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/.

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