Land-based run-off pressure on the Great Barrier Reef World Heritage Area
Land-based run-off has been identified as one of the key factors influencing the condition of the Great Barrier Reef’s ecosystem and heritage values, and therefore its outstanding universal value.
Poor water quality is a major contributor to the current poor state of many coastal and inshore marine ecosystems in the Great Barrier Reef. The Reef continues to be vulnerable to exposure to pollutants (mainly sediments, nutrients and pesticides) transported from land-based run-off.
Best practice agricultural land management is the activity with the greatest potential to improve water quality entering the Reef. It takes a significant period of time for improved land practices to influence the condition of inshore ecosystems. After a period of early uptake, the rate of adoption of agricultural best practice has slowed.
Catchment modelling indicates very poor progress against nutrient reduction targets and moderate progress against suspended sediment reduction targets. Fine sediments are of most concern for areas with shallow seagrass meadows and inshore coral reefs as they are lighter, remain suspended for longer, travel further and are resuspended with winds and tides.
Marine debris causes environmental, economic, aesthetic and human health impacts. Plastic remnants (hard plastic and film fragments) were the most prevalent marine debris type in 2014–2018 in all regions, on both the coast and islands.
The 3 most prevalent types of single-use plastic were:
- plastic drink bottles
- plastic bags
Ecosystem declines from poor water quality, particularly in inshore areas, can affect wellbeing and enjoyment of stakeholders through degraded aesthetics.
- Great Barrier Reef Outlook Report 2019, and references therein
Relevant Sustainable Development Goals’ targets
Land-based run-off pressure on the Great Barrier Reef World Heritage Area as reported in the Great Barrier Reef Outlook Report 2019.