Environment Southland

Water Story

Haere mai and welcome to our new and evolving Water Story. This is a place where you can learn more about how our fresh waterways are doing and what some of the key stresses on them are. We’ll also be sharing and profiling some of the great things that are going on across the region in an effort to help maintain and improve them. We hope you’ll come on this journey with us.

What's the current state of our water?

Rivers and Lakes in the Southland Region

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VISIT

There are many ways to consider the state of water – from whether or not it can be safely enjoyed for swimming to whether it still provides a place of habitat for indigenous fish, birds and insects. We measure the state of water in two ways - water quality monitoring and ecological monitoring. When combined, we can get an indication of the overall health of a river or stream.

How are Southland's waterways faring?

Southland's water quality is a mixed bag. The way we use the land differs across Southland so the impacts on our freshwater, whether positive or negative, are often specific to a catchment. This makes it difficult to paint a regional picture. It can also take decades for water (and any contaminants it contains) to cycle from the earth's surface through the ground to aquifers, and back to surface water systems. This means some effects we see today are legacies of past activities, and the impact of our activities today, both positive and negative, may not be seen in our waters for a long time.

The main contaminants impacting Southland's freshwater quality are nutrients (nitrogen and phosphorus), fine sediment, and disease-causing micro-organisms (referred to as microbes). Elevated nutrient concentrations can drive nuisance plant growth and be toxic to aquatic organisms and have negative health effects for humans. Sediment and faecal bacteria levels across Southland are also a concern 1.

The most sensitive parts of Southland's catchments – the estuaries, lagoons and coastal lakes – are showing signs of stress and deterioration due to excess sediment and nutrients. This includes three of Southland's main river catchments, Jacob's River Estuary, New River Estuary and Waiau Lagoon . You can read more about Southland's estuaries here.

Environment Southland's monitoring programme

We run two programmes for rivers and streams - water quality monitoring and ecological-monitoring. When the results from the two programmes are combined, they indicate the overall health of a river or stream. Read more about our monitoring programme.

Southland's Water Story

You can read about what this data means on the Environment Southland website.

The Cultural Health Index (CHI) is another measure to consider in the management of freshwater – specifically stream health. The CHI is made up of three linked components – status of the site, mahinga kai values and stream health – with each component assessed separately by the iwi/hāpu before being combined to provide a Cultural Health measure - a comprehensive assessment of the Cultural Health of the river site. Read more about the Cultural Health Index (CHI).

Are there any trends?

Data and reports from Environment Southland's monitoring networks show consistent themes about state and water quality in Southland's rivers and streams:

  • Non-point source agricultural inputs, such as leaching and runoff, are the main source of nutrient contaminants in Southland's rivers;
  • There is elevated microbial contamination in lowland rivers and streams, resulting in a high risk to human health;
  • Macroinvertebrate community health standards are not met at about 20% of our monitoring sites; and
  • There is nuisance growth of benthic periphyton in the lower Mataura, Aparima and Waiau rivers and several other lowland streams.

You can read more about the trends here (2.4MB PDF).

How's your catchment doing?

Environment Southland’s monitoring data can be found on the Land, Air, Water, Aotearoa (LAWA) website, a collaboration between New Zealand’s 16 regional and unitary councils, Cawthron Institute, and the Ministry for the Environment.

LAWA LAWA provides information on fresh and beach water quality, freshwater quantity, air quality and land cover across New Zealand. You can also find out what the state and trend is at many of our monitoring sites. LAWA is also the recommended place to check out to see whether it’s safe to swim at your local swimming spot. Explore LAWA.

To learn more about each catchment:

  • Mataura
    Mataura
  • Aparima
    Aparima
  • Waiau
    Waiau
  • Oreti
    Oreti
  • Fiordland and Islands
    Fiordland and Islands

1 https://www.es.govt.nz/Document%20Library/Research%20and%20reports/Various%20reports/Science%20reports/Water%20Quality%20in%20Southland%20-%20Current%20State%20and%20Trends%20-%20April%202017.pdf (8MB PDF).
2 https://www.mfe.govt.nz/sites/default/files/overview-of-studies-assessing-potential-impacts-setting-water-quality-scenarios.pdf(2.8MB PDF).
3 http://www.mfe.govt.nz/sites/default/files/media/Environmental%20reporting/our-fresh-water-2017_1.pdf.