Understanding river health data

Key values

Our assessments of waterway health are based on the condition of key values they support, which we rate from very low to very high. These values reflect the environmental and social importance of waterways to the community, and are represented by:

  • platypus
  • fish
  • frogs
  • birds
  • vegetation
  • macroinvertebrates
  • amenity

For each catchment and sub-catchment area, we have data on each key value's current and expected 20-year and long-term conditions.

Ratings explained

Each key value in each sub-catchment is assigned one of five ratings:

  • very high
  • high
  • moderate
  • poor
  • very poor

These ratings are averaged for each system, as waterways can vary in type, size, complexity and function, and some have better potential to support key values than others. This means the health of your local waterway may not always change, even if there is improvement over the whole system.

Our ratings also take into account the characteristics of each system, as its location influences the type and abundance of key values it can support. For example, the type and number of bird species in a coastal area will be different to those inland, but we might rate birds in both areas as being in very high condition.

The following table summaries the factors we consider when assigning ratings for each value.

​Key value Rating explanation​
Platypus​ Abundance (though not all systems will have platypus)​​
Fish Diversity of species and abundance of native species in proportion to introduced species
Frogs​ Diversity of species and abundance of native species​
Birds​ Diversity of species and abundance of native streamside and wetland species​
Vegetation​ Similarity of vegetation community to reference condition, presence of weeds;
Amount of vegetation along and out from the waterway onto the floodplain​
Macroinvertebra​tes State of stream water quality and pollution​
Amenity​ ​Satisfaction with amenity and facilities;
Number of visits to waterway​

You can read more about our key values and why they’re important on the following pages:

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