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.

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 Johnstone Basin is ‘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. Except for pesticides the results are derived from two end of catchment monitoring sites at Goondi and Central Mill, capturing 58% of the basin. Pesticide results are derived from the Coquette Point monitoring sites, capturing 70% of the basin.

The sediment score is comprised of a total suspended solids (TSS) score of 90 (‘very good’) indicating that the annual median and at least 80% of monthly medians of TSS concentrations complied with guideline values.

Nutrients scored 72.2 (‘good’) in the Johnstone basin, comprising of a DIN (dissolved inorganic nitrogen) score of 74.6 (‘good’) and FRP (filterable reactive phosphorus) score of 69.7 (‘good’), meaning that the annual medians of DIN and FRP concentrations complied with guideline values.

Using the ms-PAF method, pesticides received a low risk category with 1.8% of species affected in the waterways of the Russell basin. This resulted in a pesticide grade of ‘good’ for the basin. Pesticides were monitored at the Johnstone River CLMP site (Coquette Point), which monitors 70% of the Johnstone basin.

Compared to 2014-15 the water quality index for the Johnstone basin changed from ‘very good’ to ‘good’. The major indicator contributing to the drop in grade was ms-PAF. However for the 2015-16 period, pesticide reporting was based on monitoring at the new Coquette Point CLMP site, which is downstream of the confluence of the North Johnstone River and the South Johnstone River. Thus the score included pesticide sampling of water draining from both sub-basins. Pesticide monitoring for 2014-15 was based on samples from the North Johnstone only.

Habitat and hydrology

Hover over each segment for indicator scores and data confidence.

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

The habitat modification score of 98.5 (‘very good’) is comprised of an impoundment length score of 98.5 (‘very good’) indicating that less than 1% 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 74.77 (‘good’) with 8.1% 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 26.7 (‘poor’) with 44.3% 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 29.3 (‘moderate’) in the Johnstone 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.