Mossman Basin

The Mossman basin has an area of 479km2 with Mossman (~1,700 people) and Port Douglas (~3,200 people) being the major population centres. The basin consists of 76% natural/minimal use lands, 3% grazing, 10% sugarcane, 4% urban and 6% other land uses.

Steep mountains and hills dominate the Mossman basin, with a narrow coastal plain which has been cleared and developed with agriculture (predominantly sugarcane) and urban land uses.

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

Water quality

A water quality score and grade can't be provided for the Mossman basin in 2016-17 due to insufficient data.

The Douglas Shire Council water quality monitoring program in the Mossman River has been adapted to provide water quality data for the Report Card and is planned for inclusion in the 2017-18 reporting year.

A new end of catchment water quality monitoring site is being established through the Paddock to Reef program, and the data will be made available for the Wet Tropics Report Card in future years.

Habitat and hydrology

The habitat and hydrology index is comprised of four longer-term indicator categories that are updated every four years: wetland extent, riparian extent (both to be updated for 2017-18), invasive weeds (to be updated for 2019-20), habitat modification (impoundment length (to be updated for 2018-19) and fish barrier indicators (in development)). The flow indicator for the Mossman basin (reported annually) was introduced in 2016-17.

Changes in the habitat and hydrology index scores over the last three years are as a result of the addition of indicators rather than changes in the indicator scores themselves.

The habitat and hydrology index changed from ‘moderate’ in 2015-16 to ‘good’ in 2016-17 with the score increasing from 55 to 63 due to the addition of the flow indicator.

The habitat modification score of 100 (‘very good’) is comprised of an impoundment length score of 100 (‘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 Mossman basin scored 68 (‘good’) with 11.5% loss from pre-clear extent to 2013. It is expected the uplands would generally have better extent due to protected areas and less development. Less extent in the lowlands is due to development and land use.

Wetland extent scored 17 (‘very poor’) with 58.8% loss of palustrine (freshwater) wetlands from pre-clear to 2013. These results reflect a high level of historic loss due to development.

The invasive weeds indicator scored 36 (‘poor’) in the Mossman basin and represents substantial impacts of aquatic weeds within the Mossman freshwater system including hymenachne (Hymenachne amplexicaulis), salvinia (Salvinia molesta), water hyacinth (Eichornia crassipes) and pond apple (Annona glabra).

The Mossman basin was graded as ‘very good’ for flows during 2016-17. Flows in the Mossman basin were similar to predevelopment flows in their capacity to support the key ecological assets of water holes, low flow spawning fish, riffle habitats and fisheries production.

More information on the results of the flow indicator is available in the results technical report.


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.