Modelling and monitoring

Modelling program

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.

Summary of catchment pollutant loads results from Report Card 2017 and 2018 (PDF, 869.6KB) .

Catchment loads modelling program technical reports:

Regional technical reports were produced covering 2009–2013:

Monitoring program

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.

The catchment loads monitoring results are reported through an interactive Story Map :

The loads for all measured contaminants were previously released in an annual technical report:

Last updated
30 August 2019