Estuary Health

Estuaries are important natural places that sustain key aquatic species and, provide good habitat and cultural, social, economic and ecological services that are important to a region. Estuaries managed in sustainable ways, they support a variety of ongoing economic benefits to communities and industry.

The map below shows daily health/condition scores derived from real-time environmental data collected via water quality probes deployed at 5 locations along the Lower Hawkesbury Estuary. These probes take measurements every 15 min of water temperature, salinity, chlorophyll-a and turbidity and are calibrated every 3 weeks in summer and every 5 weeks in winter. The estuary health/condition grades shown on the map are calculated based on chlororophyll-a and turbidity daily data which is compared to baseline conditions/levels. Trigger values (80th percentile of all data available for reference estuaries as defined by OEH * ) are calculated to highlight when an indicator is outside the expected range. The level of compliance against the trigger values are reported based on the level and frequency of exceedance. Results showing poor grades will trigger further investigation or a management action. For information on the analysis used to calculate the estuarine health scores/grades, please refer to OEH guidelines and protocols*.

  Very Good   Good   Fair   Poor   Very Poor


Grade % in the Last 12 Months
Location Latest Grade Very Good Good Fair Poor Very Poor
Bar Island  Fair 08 Dec 2019 0 21 67 7 5
Calabash Bay  Poor 08 Dec 2019 0 6 27 34 33
Courangra Point  Fair 08 Dec 2019 7 30 45 13 6
Gunyah Point  Good 08 Dec 2019 18 50 30 1 1
Laughtondale  Fair 08 Dec 2019 0 11 40 31 18


Report card grades, definitions and descriptions (from NSW OEH, 2013)*

GradeResultDefinition (example)Description
Very GoodThe indicators measured meet all of the benchmark values for almost all of the time period.Equivalent to the best 20% of scores in the state
GoodThe indicators measured meet all of the benchmark values for most of the time period.Equivalent to the next 30% of good scores
FairThe indicators measured meet some of the benchmark values for some of the time period.Equivalent to the middle 30% of scores
PoorThe indicators measured meet few of the benchmark values for some of the time period.Equivalent to the next 15% of poorer scores
Very PoorThe indicators measured meet none of the benchmark values for almost all of the time period.Equivalent to the worst 5% of scores in the state

* NSW OEH guidelines and protocols »» Assessing estuary ecosystem health: sampling, data analysis and reporting protocols (2013)
NSW Natural Resources Monitoring, »» Evaluation and Reporting Program.
NSW Government, »» Office of Environment and Heritage.