RRRD030 Pollutant load estimation for Great Barrier Reef catchments: Accounting for the uncertainty in monitoring and modelled data using data assimilation techniques


Project Leader

Petra Kuhnert




Go Straight to the Publications From This Project

Project Overview

Under the Reef Water Quality Protection Plan (Reef Plan) there is a requirement to reduce the export of nutrients, sediments and pesticides to the Great Barrier Reef (GBR) lagoon. Underpinning strategies, such as the Reef Rescue Water Quality Grants, the Paddock to Reef Integrated Monitoring, Modelling and Reporting Program (P2R program) and Reef Rescue R&D are aimed at reducing and measuring contaminant export from catchments through the introduction of improved land management practices.

The approach for loads estimation feeding into the P2R program baseline Report Card used catchment models to estimate loads from a subset of catchments in the GBR and monitoring data for the remainder (with quantified uncertainties), providing two different estimates of loads that need to be integrated into the P2R program Report Card (see Kroon et al. (2011) for an example and Kuhnert et al. (2011) for details regarding the statistical model developed for monitoring data). Furthermore, it is envisaged that future reports will only use catchment models for reporting loads, using monitoring data to calibrate models. This approach only addresses uncertainties in the catchment model parameters but does not address key uncertainties surrounding structural errors in the model and errors around the monitoring data used to calibrate the models.

This Project Will Deliver

  • Provision of a robust framework for coupling P2R program catchment monitoring data with the physical process that underpins the process-based model (e.g. Source Catchments) to produce an estimate of loads with uncertainties that incorporates the errors associated with the model and the measurements collected about the process.
  • Illustration of the methodology using the Burdekin as a trial area in the GBR catchment.
  • Development of realistic management scenarios for the trial area within the modelling framework to investigate changes due to management.
  • Engagement with Queensland Government modelling and monitoring staff to ensure that the outputs can be used to facilitate P2R program reporting.

PROGRESS UPDATES for this project are summarised here

Study Areas

  • Burdekin case study, focusing on the Upper Burdekin catchment and Weany Creek subcatchment.

Associated Reef Rescue R&D Research

  • RRRD032 Improving grazing management practices to enhance ground cover and reduce sediment loads.

Related External Research

Paddock to Reef Program
  • Source Catchments modelling and load estimation.
  • Requirement to report on loads and assess under prescribed targets for nutrients and sediments - provides uncertainty estimates for loads that are interpretable.
  • Assimilate all sources of available information.
  • Assess monitoring requirements and identify where more data is required or better information about the parameters of the physical process are needed.

Publications From This Project

The Research Outcomes Report for RRRD030 is available for download via the Final Report page. This report should be cited as:

Kuhnert, P.M., Pagendam, D., Bartley, R., Searle, R., Peterson, E., Leeds, W.B., Wikle, C.K., Ellis, R., Turner, R., Waters, D., Dougall, D., Lewis, S., Bainbridge, Z. and Brodie, J. (2013). Integrating measurements with models for improved confidence in pollutant loads estimation. Project RRRD030 Pollutant Load Estimation for Great Barrier Reef Catchments (GBR): Accounting for Uncertainty. Report to the Reef Rescue Research and Development Program. Reef and Rainforest Research Centre Limited, Cairns (39pp.). ISBN: 978-1-925088-32-8.

The results of the project are also summarised in several presentations delivered at Reef Rescue R&D forums; visit the Events page.


Pagendam, D.E., Kuhnert, P.M., Leeds, W.B., Wikle, C.K., Bartley, R. and Peterson, E.E. (2014). Assimilating catchment processes with monitoring data to estimate sediment loads to the Great Barrier Reef. Environmetrics, Special Issue 25: 214-229.

Bainbridge, Z., Lewis, S., Smithers, S., Kuhnert, P., Henderson, B., Brodie, J. (2014). Fine-suspended sediment and water budgets for a large, seasonally dry tropical catchment: Burdekin River catchment, Queensland, Australia. Water Resources Research 50: doi:10.1002/2013WR014386.

Lewis, S., Bainbridge, Z., Kuhnert, P.M., Sherman, B.S., Henderson, B., Dougall, C., Cooper, M. and Brodie, J.E. (2013). Calculating sediment trapping efficiencies for reservoirs in tropical settings: A case study from the Burdekin Falls Dam, NE Australia. Water Resources Research 49, 1017–1029, doi:10.1002/wrcr.2011.

Related publications

Kuhnert, P.M., Henderson, B.L., Lewis, S., Bainbridge, Z., Wilkinson, S.N. and Brodie, J. (2012). Quantifying total suspended sediment export from the Burdekin River catchment using the loads regression estimator tool. Water Resources Research, 48. DOI: 10.1029/2011WR011080