Barron Estuary

The area of the Barron estuary reporting zone can be defined by the pre-cleared extent of mangrove and saltmarsh remnant vegetation which is characterised by species that require periodic inundation of sea water. This area extends approximately 10.5 km north and 4.5 km south of the river mouth along the coastline and extends approximately 5.5 km inland. The area includes several tributaries that drain into the Barron River and coastal streams that drain directly into the sea.

The assessment area of riparian extent extends further up the river than the mangrove and salt marsh communities to the upper tidal limit and includes vegetation types that are more typical of freshwater environments.

Land use within and adjacent to the Barron estuary area is dominated by urban development. The northern beach suburbs of Machans Beach, Yorkeys Knob and Holloways beach, and the Cairns suburbs of Aeroglen, Cairns North and Whitfield overlay the estuary area.

Industries within the estuary area include the Cairns international and domestic airport, quarries, aquaculture and sugarcane.

Key results

The Barron estuary grade remained ‘moderate’ and the score increased from 50 to 56.

• Water quality remained ‘moderate’ with the score increasing from 55 to 60.
• Turbidity improved from ‘good’ to ‘very good’.
• Filterable reactive phosphorus (FRP) improved from ‘poor’ to ‘moderate’.
• Chlorophyll a declined from ‘good’ to ‘moderate’.
• The habitat and hydrology index remained ‘moderate’ and increased from 44 to 53.
• Mangrove and saltmarsh extent remained ‘moderate’ with no recorded habitat loss since 2019.
• Shoreline mangrove habitat condition remained ‘good’ since the 2023-24 survey.
• Riparian vegetation extent remained ‘poor’ with no recorded habitat loss since 2019.
• The flow indicator improved from ‘moderate’ to ‘good’ due to the return of a more typical rainfall pattern for the region. Poorer scores in 2023-24 were influenced by Severe Tropical Cyclone Jasper (TC Jasper) and the early onset of the wet season and intense rainfall and flood events from mid-December.

The diagram below shows the detailed results for each indicator by year. Click on the timeslider to see data from previous years.