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.

The Barron estuary grade remained ‘moderate’ in 2022-23 and the score decreased slightly from 51 to 50, since the previous year.

Key results

• The water quality grade for the Barron estuary remained ‘moderate’ and the score decreased slightly from 46 to 45, although several indicators changed substantially since the previous year.
• Chlorophyll a improved from ‘poor’ to ‘good’.
• Filterable reactive phosphorus (FRP) declined from ‘moderate’ to ‘very poor’.
• Dissolved inorganic nitrogen (DIN) remained ‘poor’ whilst the score decreased from 37 to23.
• Turbidity declined from ‘good’ to ‘moderate’.
• Dissolved oxygen improved from ‘moderate’ to ‘good’.

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