Barron Basin

The Barron basin has an area of 2189 km2 with Mareeba and Atherton as the main population centres. The basin consists of 29% natural/minimal use lands, 31% grazing, 18% forestry, 8% other crops (including bananas), 3% sugarcane, 3% dairy, 5% urban and 4% other land uses. The Barron River is the most modified river in the Wet Tropics region and is heavily regulated by water supply infrastructure. The basin has a large upper catchment on the Tablelands and a smaller lower catchment north of Cairns where it discharges into Trinity Bay. A major dam is situated at Tinaroo Falls at the northern end of Lake Tinaroo. The Barron River is a strong story place for Aboriginal custodians.

Scroll down for further detailed results for each indicator group.

 

Grading

gradesa1

very good

gradesb1

good

gradesc1

moderate

gradesd1

poor

gradese1

very poor

insufficient data

Confidence surrounding the data used in the circle diagrams has been assessed using a multi-criteria framework.

confidence

Water quality

Hover over each segment for indicator scores and data confidence.

The overall water quality grade in 2015-16 for the Barron basin is ‘very good’.

Water quality grades are based on aquatic ecosystem guidelines for protection of freshwater systems, and are not based on load reduction targets for the marine environment. The results are derived from the end of catchment monitoring site at Myola, capturing 89% of the basin.

The sediment score is comprised of a total suspended solids (TSS) score of 89.1 (‘very good’) meaning that the annual median and at least 80% of monthly medians of TSS concentrations complied with guideline values.

Nutrients scored 76.6 (‘good’) in the Barron basin, comprising of a DIN (dissolved inorganic nitrogen) score of 63.1 (‘good’) and FRP (Filterable Reactive Phosphorus) score of 90.0 (‘very good’)).

Pesticides are not monitored in the Barron basin, therefore a score and grade cannot be provided.

Compared to 2014-15 the Barron increased from ‘good’ to ‘very good’. The change was driven in part by a substantial increase in score for total suspended solids. Lower concentrations of total suspended solids in 2015-16 for the Barron were likely due to the very low annual discharge and an absence of the out of season local rainfall events that occurred during 2014-15.

Habitat and hydrology

Hover over each segment for indicator scores and data confidence.

The overall habitat and hydrology grade for the Barron basin in 2015-16 is ‘moderate’.

The habitat modification score of 36.3 (‘poor’) is comprised of the impoundment length indicator showing 7.7% of the total length of the waterways with a stream order of 3 or higher are impounded by artificial structures. Tinaroo Dam is the largest impoundment in the basin.

The fish barrier indicator method is still being developed and will be available in future report cards.

Riparian extent for the Barron basin scored 68.9 (‘good’) with 11.1% loss from pre-clear extent to 2013. It is expected that the majority of loss is due to development and land use.

Wetland extent scored 11.7 (‘very poor’) with 72.2% loss of palustrine (freshwater) wetlands from pre-clear to 2013. These results reflect a high level of historic loss due to development. Wetland losses in future reporting periods will be minimal.

Habitat modification, riparian extent and wetland extent are updated every four years and have not changed since 2014-15. The data for riparian and wetland extent are due to be updated in 2018.

The invasive weeds indicator is new for the 2015-16 period and scored 56.6 (‘moderate’) in the Barron basin.

The habitat and hydrology index score and grade differed between 2014-15 and 2015-16 due to the introduction of the invasive weeds indicator.

The method for the flow indicator is currently under development and will be available for future report cards.

Fish

Hover over each segment for indicator scores and data confidence.

The fish index is currently under development and will be available in future report cards.

Further information on the methods used to produce the scores and grades and detailed results can be found here.