Modelling and monitoring
The Great Barrier Reef Catchment Loads Modelling Program estimates average annual loads of key pollutants (sediment, nutrients and pesticides) for each of the 35 catchments draining to the Great Barrier Reef as part of the Paddock to Reef program. It reports on baseline levels and the change in loads for each subsequent year due to adoption of improved land management practices. This assesses progress towards the Reef water quality targets with the latest results available in Report Card 2019.
For more information about how the loads are modelled, refer to the Methods to create report card .
An independent review of the modelling program was undertaken in 2019.
Catchment loads modelling program technical reports:
- Updated methodology and results for Report Card 2015
- Updated methodology and results for Report Card 2014
Regional technical reports were produced covering 2009–2013:
The Great Barrier Reef Catchment Loads Monitoring Program tracks long-term trends in water quality entering the Great Barrier Reef lagoon from adjacent catchments as part of the Paddock to Reef program. The monitoring data is used to validate the catchment water quality models that track progress towards the Reef targets.
This involves monitoring 43 sites in 20 key catchments for sediment and nutrients and a further 19 sites for pesticides. Samples are collected on a monthly basis during ambient (low flow, dry season) conditions and every few hours to daily during high flow events in the wet season.
The concentrations of contaminants are determined and the volume of water flowing in the rivers is then used to determine the total amount of each contaminant (i.e. the load) that flows past the sampling sites.
For more information about how the loads are monitored, refer to the Methods to create report card .
You can also access more information about the methods used to estimate the pesticide risk metric, pesticide risk baseline and the pesticide condition results.
The catchment loads monitoring results are reported through an interactive Story Map:
- 2018-2019 Great Barrier Reef Catchment Loads Monitoring Program Report Summary (interactive storymap)
- 2017-2018 Great Barrier Reef Catchment Loads Monitoring Program Report Summary (interactive story map)
The loads for all measured contaminants were previously released in an annual technical report:
- Last updated
- 17 February 2021