Lake Macquarie water health report card

Find out the water health of Lake Macquarie. Every year, water quality samples are taken from a number of locations around the lake to learn more about how our waterways are doing, identify trends and guide future management actions.

The report card helps us compare current conditions with the condition we would like our waterways to be. Think of it as a ‘health check’ for our waterways.

The Department of Climate Change, Energy, the Environment and Water (DCCEEW) has been monitoring the health of Lake Macquarie since 2011.

The results of the report card can be used to guide future management actions and ensure the long-term ecological health of the lake.

The annual mean water quality monitoring data for 2023-2024 continue to show reasonable results, with water quality maintained in most areas. Monitoring data indicates that whilst 2023-2024 saw improved water quality compared to 2022-23, it is the fifth successive year of declining water clarity in the lake (due to high sediment inflows), particularly in Cockle Bay, Fennell Bay and near Dora Creek

Secchi depth is an indicator of water clarity determined by measuring the greatest water depth at which a special disk can be read. The improvement in average Secchi depth from 2001-2002 (1.739m) to 2023-2024 (3.665m) was 210.75 per cent. Reduced rainfall intensity compared to the previous year has resulted in an improvement for this reporting year, with the Secchi depth increasing 22 per cent (0.71m) from 2022-2023 (2.995m) to 2023-2024 (3.665m). The five yearly average water clarity for the 2019-2024 was 3.499m, which is over half a meter less than the 2014-2019 average of 4.092m.  

In addition to measuring water clarity, annual scorecards for aquatic ecosystem health of Lake Macquarie have been produced based on ‘turbidity’, ‘chlorophyll-a’ (a measure of algae within the water column), ‘overall water quality’, and ‘seagrass depth range’.

Overall, ecological health in central part of Lake Macquarie during 2023-2024 continued to be very good, with all sites in the lake’s main basin scoring straight A (very good) grades for ‘turbidity’, ‘chlorophyll-a’, ‘overall water quality’, and ‘seagrass depth range’.

Cockle Creek retained a C (fair) grade for ‘overall water quality’ despite both ‘turbidity’ and ‘chlorophyll-a’ dropping a grade.  Dora Creek saw a decline in ‘overall water quality’ to C (fair) due to a drop in ‘turbidity’ (the February 2024 result was over eight times the turbidity trigger value). Fennell Bay saw declines in the grades for ‘overall water quality’, ‘turbidity’ and ‘chlorophyll-a’, but an improvement in the ‘seagrass depth range’ resulting in the overall ecological health grade remaining as C (fair).  

2023-24 saw improvements in the ‘seagrass depth range’ for all monitoring sites. These increases were 4.7% for the Northern Zone, 13% in the South-East Zone, 21% in the South-West Zone and 42% in Fennell Bay.  

Yearly rainfall between the sampling period of July 2023 to June 2024 was relatively consistent with long-term averages, although there was higher than average rainfall recorded in April, May and June 2024.

Click on the blue location marker below to see this year’s results by specific location. The Report Card grades the health of the waterways in a similar way to school Report Cards, with a grade ranging from A (very good) to F (very poor).