Herbert Basin

In the upper catchment of the Herbert Basin the main towns are Herberton (population 934) and Ravenshoe (population 1,442 ) and are located on the Atherton and Evelyn Tablelands. The largest town in the Herbert Basin is Ingham, located in the lower catchment, and has a population of 4,767.

The upper basin consists of the vast north-western section upstream of the Herbert River Falls and forms the most southern extent of the Atherton and Evelyn Tablelands. There are extensive grazing areas in the western area of the upper catchment – and much of the area was subject to historic alluvial tin mining.

The intermediate basin includes the Herbert River Gorge and consists mostly of National Parks, State Forests and other State Land, some within the Wet Tropics World Heritage Area.

The lower basin is the river delta or floodplain. It is dominated by sugarcane and there is some irrigation in the southern-most area of the catchment. Many of the streams and tributaries discharge directly into Halifax Bay.

The Herbert Basin has an area of 9,842 km2 and consists of 27% natural/minimal use lands, 56% grazing, 8% sugarcane, 4% forestry and 4% other land uses.

The overall grade for the Herbert basin is moderate (C). Water quality and habitat and hydrology contributed to this grade.

Scroll down for further detailed results for each indicator group.

Grading

gradesa1

very good

gradesb1

good

gradesc1

moderate

gradesd1

poor

gradese1

very poor

gradesnd1

insufficient data

gradesna1

not applicable

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 2014/15 for the Herbert Basin is ‘moderate’.

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 one end of catchment monitoring site at Ingham, capturing 87 per cent of the basin.

The sediment score of 100 (good) is comprised of a total suspended solids (TSS) score of 100 (good) indicating that the annual median of TSS complies with guideline values.
Nutrients scored 93.22 (moderate) in the Herbert Basin, comprising of a DIN (dissolved inorganic nitrogen) score of 86.45 (moderate) and FRP (filterable reactive phosphorus) score of 100 (good) indicating that the annual median of FRP complies with guideline values.

Using the ms-PAF method, contaminants received a low risk category with 1.58 per cent of species affected in the waterways of the Herbert Basin. This resulted in a contaminant grade of ‘good’ for the basin.

Habitat and hydrology

Hover over each segment for indicator scores and data confidence.

The overall habitat and hydrology grade for the Herbert Basin in 2014/15 is ‘moderate’.

The habitat modification score of 100 (very good) is comprised of an impoundment length score of 100 (very good) indicating that less than 1 per cent of the total length of the waterways with a stream order of 3 or higher are impounded by artificial structures. The fish barrier indicator method is still being developed and will be available in future report cards.

Riparian extent for the Johnstone basin scored 100 (very good) with 3.9 per cent loss from pre-clear extent to 2013. It is expected that the majority of loss is in the lowlands due to development and land use.

Wetland extent scored 25.1 (very poor) with 51.1 per cent 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.

Freshwater riparian extent and wetland extent are updated every four years and the figures in the pilot report card are the most current. The data for both are due to be updated in 2017/18.

The methods for the flow and invasive weeds indicators are 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.