Environment Southland

What's the current state of our water?


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. Read more about our monitoring programme.

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 or a waterbody type.

The main contaminants impacting Southland's freshwater quality are nutrients (nitrogen and phosphorus), fine sediment, faecal bacteria and E.coli. 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.

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.

Learn more from a large range of scientific reports here.

What does the latest assessment tell us about our environment?

Environment Southland monitors water quality at over 100 river, lake and estuary sites and more than 1000 groundwater sites so that we can build an understanding of environmental health across the region.

Environment Southland has completed an assessment of our current state compared with the draft environmental outcomes.

The assessment uses the “ABCD” banding system to present environmental state for three time periods (2010, 2016 and 2019). Wherever possible, we have compared the current state with the relevant draft environmental outcome.

Read out more about the draft environmental outcomes.

"A" generally means "very good", "B" means "good", "C" means "fair" and "D" means "poor". For some environmental outcomes, national bottom lines have been set. These are generally at the boundary between “C” and “D” band and must be met by every region in New Zealand. The draft environmental outcomes are either at or above these bottom lines.

The results show that the size of the gap to achieve draft environmental outcomes varies for different characteristics across different catchments and waterbodies.

Delve into the detail on this map - change the measurements and check out what we’re aiming for at each site.

Check out this graphic for a summary of some of our monitoring information

Southland's Water Story

Data highlights the challenge we have in front of us to turn things around. There is a substantial gap in many parts of Southland between current state and the desired environmental outcomes. The four key problem contaminants are:

  • Faecal bacteria (E. coli and/or Enterococci)
    There is a substantial gap to close to meet environmental outcomes for E. coli. To meet the outcome for groundwater drinking supply and human health for recreation, improvements will be needed at many sites in our groundwater, and across much of lowland Southland’s lakes, rivers and estuaries. Some sites in the hill river class also did not meet E. coli outcomes. Most sites in mountain rivers, deep lakes and many open coast sites do meet objectives for E. coli and/or enterococci.
  • Nutrients (nitrogen and phosphorus)
    There is a substantial gap to meet environmental outcomes at some sites for nutrients like nitrogen and phosphorus, particularly in lowland Southland waterways. High levels of nutrients also impact on other environmental outcomes such as periphyton and macroinvertebrates in rivers, phytoplankton and macrophytes in lakes, and macroalgae and gross eutrophic zone (GEZ) conditions in estuaries.
  • Sediment
    There is a substantial gap to close to meet environmental outcomes at some sites, particularly in lowland rivers and lakes and in estuaries.

Other measures or factors

While these four key contaminants (E. coli, nitrogen, phosphorus, sediment) contribute to many of the failures to meet draft environmental outcomes, the outcomes will not be achieved by only focusing on these contaminants. Many other factors also contribute to the problems and will all need to be considered as part of the solution.

  • These include,
    • Water quantity (water flow and level) plays an important part in supporting healthy ecosystems.
    • Improvements to riparian and instream habitats for rivers, and improvements to wetlands around some lakes and estuaries.
    • Biodiversity enhancements, invasive weed and pest control, and restoration projects.
    • Innovative technological and/or engineering projects for some situations.
    • Climate change may also affect the environmental outcomes (objectives) in future.

Read more about the results of this latest assessment in the report Current environmental state and the "gap" to draft freshwater objectives for Southland".

Find out more about the state and outcomes on the map by delving into the data.

Key results for groundwater:

Human health for drinking

  • At a regional scale approximately one third of groundwater bore monitoring sites fail the draft E. coli environmental outcome for drinking water supply (human health).
  • The failing sites are spread across four catchments (FMUs) - Waiau, Aparima, Ōreti and Mataura.
  • At a regional scale, approximately one third of sites currently fail the draft environmental outcome for nitrate for drinking water supply (human health).
  • To be safe for drinking, groundwater in some areas of the region will need substantial improvement in both E. coli and nitrate contamination.

Ecosystem health

  • The nitrate concentration results organised by Groundwater Management Zone (GMZ) show that while currently 4 zones are in A (very good) or B band (good), most zones (16) are in C band (fair) and a significant number (7) are in D band (poor).
  • To achieve an outcome better than C band for nitrate toxicity in groundwater, considerable improvement is needed in some areas./li>

Key results for rivers:

Regional scale

  • Periphyton and macroinvertebrates are key measurable attributes for ecosystem health, and results failed to meet the draft environmental outcomes at some sites across the region, particularly in lowland areas.
  • E. coli is a key contaminant affecting human health for recreation and results failed the draft environmental outcomes at a majority of sites across the region and at all monitored swimming sites.

Freshwater Management Unit (FMU) scale

  • The ‘Fiordland and islands’ FMU is distinct for being in a high quality, largely natural state that likely meets all draft environmental outcomes, even though we have few data to show this.
  • The Aparima, Mataura and Ōreti Freshwater Management Units all have sites that fail to meet the outcomes with respect to nutrients, sediment and E. coli, particularly in the lowland river and springfed streams.
  • The Waiau FMU is distinct for being in generally better condition than the other three modified FMUs for most attributes, but with the exception of mat cover periphyton and cyanobacteria for which it is worse.

River classes scale

  • Nutrients, sediment and E. coli are key contaminant issues in Lowland Soft Bed and Lowland Hard Bed rivers.
  • Nutrients, sediment and E. coli are also important but less of an issue in Hill and Lake Fed rivers.

Key results for lakes:

Lake condition and draft environmental outcomes

  • Nutrients are the main contaminants causing some lakes to fail the draft environmental outcomes
    • Lowland Shallow Lakes and Brackish Lakes and Lagoons are particularly at risk of elevated nutrients
    • Nutrients contribute to failures to meet phytoplankton environmental outcomes
  • Other factors contributing to the failure to meet environmental outcomes in some lakes include:
    • Lake flows and levels
    • The quality of wetlands around lake margins
    • Invasive macrophytes
    • Pest fish species
    • Climate change effects
  • Failure to meet environmental outcomes relating to human health for recreation is due to the presence of faecal bacteria (E. coli), with Lowland Shallow Lakes and Brackish Lakes and Lagoons most at risk.
  • Lake water quality is generally very good in Southland’s Deep and Natural State lakes.

Key results for estuaries and open coast:

Estuary condition and draft environmental outcomes

  • The following estuaries are showing signs of eutrophication (nutrient enrichment) due to large amounts of nutrient and sediment reaching the estuary:
    • New River Estuary
    • Jacobs River Estuary
    • Toetoes (Fortrose) Estuary
  • They all have areas that are currently in the D band (poor) for macroalgae, Gross Eutrophic Zone (GEZ), mud content and sediment oxygen levels.
  • A reduction in nutrient and sediment inputs would be needed to improve all these attributes above D band (poor) at all sites in these estuaries.
  • Faecal bacteria contamination (as indicated by both E .coli and Enterococci) is a key contaminant affecting the value of human health for recreation in estuaries and the open coast, and caused D band (poor) grades at some sites.
  • Reduced faecal bacteria would be needed to achieve at least C band (fair) or better at all estuary and open coast sites.

Read more about the results of this latest assessment in the report Current environmental state and the "gap" to draft freshwater objectives for Southland".

Find out more about the state and outcomes on the map by delving into the data.