Johnstone Basin

The Johnstone basin population is 15,000 and largely concentrated within the towns of Innisfail, Malanda, Millaa Millaa and South Johnstone.

The two key tributaries of the Johnstone River include the North Johnstone and South Johnstone Rivers. The North Johnstone River basin can loosely be divided into three sections: the upper ‘mixed land use’ area consisting of dairy, beef grazing, sugar cane, horticulture (potatoes) and the townships of Millaa Millaa and Malanda; the middle area contains steep forested areas, much of which is in the Wet Tropics World Heritage Area; and the lower reaches characterised by low sloping hills and coastal floodplains. These lower areas contain a majority of the agricultural areas and include the larger townships of Innisfail and South Johnstone.

The Johnstone Basin has an area of 2,326 km2 and has a relatively high proportion of natural/minimal use lands (55%). The remaining area contains 16% grazing, 12% sugarcane, 6% dairy (in the upper catchment), 3% bananas, 1% other crops, 2% urban and 4% other land uses.

The overall grade for the Johnstone 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 Johnstone 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 from two end of catchment monitoring sites at Goondi and Central Mill, capturing 58 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 96.38 (moderate) in the Johnstone basin, comprising of a DIN (dissolved inorganic nitrogen) score of 100 (Good) indicating that the annual median of TSS complies with guideline values, and FRP (filterable reactive phosphorus) score of 92.76 (moderate).

Using the ms-PAF method, contaminants received a very low risk category with 0.58 per cent of species affected in the waterways of the Russell basin. This resulted in a contaminant grade of ‘very good’ for the basin. Contaminants were monitored at the North Johnstone CLMP site only (Goondi) which monitors 41% of the Johnstone Basin.

Habitat and hydrology

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The overall habitat and hydrology grade for the Johnstone 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 (good) with 8.1 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 28.5 (very poor) with 44.3 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.