The quality of water flowing to the Great Barrier Reef has improved according to the latest Wet Tropics Report Card.
Released today, the Report Card grades nearly 90 per cent of the region’s freshwater rivers and estuaries as ‘Good’ or ‘Very good’, with the Daintree catchment the highest performer.
Inshore and offshore marine areas fared less well with Moderate or Poor grades, mostly due to the poor condition of seagrass still recovering from cyclones and severe floods in 2009-2011.
The Report Card assesses the condition of the nine river catchments in the Wet Tropics from the Daintree to the Herbert, using data from the July 2016-June 2017 reporting period.
It is produced by the Wet Tropics Healthy Waterways Partnership as an initiative of the Reef 2050 Plan – an Australian and Queensland Government framework for protecting and managing the Great Barrier Reef including tracking changes in the health of waterways.
Chair, Professor Steve Turton, said the Partnership has been gradually adding more monitoring to the program to provide a more complete picture of waterway health in the Wet Tropics region.
“This is our third report card and it is becoming a really useful tool for the community as we plug the monitoring gaps identified in the pilot report card. This year the Partnership invested in a new flow indicator as an additional assessment tool and we began fish surveys in the Mulgrave and Russell catchments that will be expanded over the next two years. Douglas Shire Council has also modified its water quality monitoring in the Dickson Inlet, enabling us to include a water quality index,” he said.
While the majority of grades are positive across the region this year, Professor Turton cautioned that continuing below-average rainfall is a significant factor in the positive results and this is likely to change in the next reporting period following the severe flooding in early 2018.
“Lower rainfall is associated with lower loads of nutrients and sediments running off to the Reef and over the last three reporting periods we’ve had very dry climatic conditions. This trend broke with extensive flooding in early 2018, which is likely to have flushed pollutants off the land into rivers and creeks. So it will be will be interesting to see how the grades fare in next year’s report card,” he said.
While poor water quality has been identified as a stressor on the Great Barrier Reef, Professor Turton said the latest science indicates that climate change is the biggest threat as marine heatwaves, which are drivers of mass coral bleaching events, become more common.
“During the 2016-17 reporting period we had high sea temperatures which resulted in a second back-to-back coral bleaching event. Despite this, inshore coral communities suffered only minor loss of coral cover. The surveys for offshore coral were conducted before the second bleaching event that largely affected reefs between Cairns and Townsville, so next year’s report card will provide a better picture of how offshore coral grades were affected,” he said.
“While climate change is a global issue, a significant difference can be made by improving water quality to give the Reef a better chance of recovery from future bleaching events.”
This year’s Report Card highlights some of the actions occurring across the Wet Tropics to improve waterway health including restoring priority wetlands along the coast, fixing gully and streambank erosion and supporting farmers to change land management practices.
Several catchment repair systems are also being trialled in the Johnstone and Tully catchments as part of the Queensland Government-funded Wet Tropics Major Integrated Project. Some of these engineered solutions include bioreactors, constructed wetlands and sediment basins.
Professor Turton said the Report Card is a significant achievement and he is encouraged by the commitment and enthusiasm shown by the Wet Tropics community.
“We now have over 50 partner organisations working together to produce the Report Card and all of them are driven to do what they can for aquatic ecosystems and waterway health, which ultimately means a more resilient Great Barrier Reef for future generations,” he said.