Coastal wetland systems repair across GBR catchments – values based causal framework validation

Nathan Waltham
Led by: Dr Nathan Waltham, JCU


Project Summary

Conservation and repair of the coastal wetland ecosystems’ in the Great Barrier Reef catchments have come into focus following media converging on the point that the reef health and land use in catchments has been compromised.  While on-ground wetland repair investment activities are underway, data to demonstrate water quality and biodiversity return for the investment is not available.  Here we continue working with project partners, further contributing to change management practices, consolidate new project partnerships, and road test the Queensland Wetlands Values Based Causal Framework using existing and new data.


Project Publications
Final Report 1
Final Report 2




Project Webinar – 17th November 2020


Project Description

Problem – coastal wetland degradation

Coastal wetlands adjacent to the Great Barrier Reef (GBR) have incredible environmental, cultural and economic value. Despite this, over 70% of GBR coastal wetlands have been modified, impacted or lost entirely because of continuing land use change (such as agricultural, aquaculture, peri-urban/urban, and industrial expansion). Of the wetlands remaining many provide severely reduced habitat value due to alien weed infestation and poor water quality. A large number of coastal wetlands have also lost their connection with estuaries that flow into the GBR lagoon, which can impact marine and freshwater aquatic species that have a critical estuary lifecycle phase, and rely on this connectivity between the reef and shallow tidal and freshwater wetlands.

Response – coastal wetland system repair

In order to halt and reverse wetland decline, State and Federal government agencies continue to invest significant funding into coastal wetland system repair, mainly coordinated through NRM bodies. In addition to these existing investments there are also large amounts of funding on the horizon, that will be delivered through government and private investments.

The key problem is that there is a lack of scientific data to support and give surety that on-ground wetland repair investment achieves water quality, biodiversity returns and other services. Many existing wetland improvement projects have the objective of reducing invasive aquatic weeds, improving water quality and increasing usable habitat and marine connectivity for aquatic species, however, scientific data evaluating the degree to which this actually happens is not available. This is particularly true for long-term impacts beyond the first few years of remedial management. Scientific data and long term evaluation methods are therefore particularly necessary to track the progress against broader program objectives, in particular those contained in a number of policies and planning documents (e.g., Wetlands in the Great Barrier Reef Catchments Management Strategy 2016 – 21, Reef 2050 Long Term Sustainability Plan (2018), Reef Water Quality Protection Plan 2017-2022, and regional NRM plans and WQIPs).

How Research Addresses Problem

This project will direct efforts towards providing further support to partnerships under Project 3.3.2, but will also support new partners seeking support from research to evaluate their operations.  In addition, the extension will take all the data generated and build case studies for each wetland site under the recently completed (September 2018) Values Based Causal Framework by the Queensland Wetlands Program team. With these case study reports, future project sites could be critically analysed early to determine whether the project is suitable and could possibly achieve the outcomes expected.

Key objectives:

  • Undertake field surveys to collect data to profile and characterise biodiversity, and water quality prior to, during and after on-ground action at project sites,
  • Extend science evaluation support to new project partners, where this project will generate new, additional, data to facilitate additional end user practice changes;
  • Extend Indigenous Ranger trainee to the end of this project, to continue maintaining scientific equipment deployed, to examine seasonal and inter-annual changes in wetland conditions;
  • Generate case studies using all generated data, following the Queensland Wetland team Values Based Causal Framework


Evaluation of Round Hill Reserve feral pig fence, Lilliesmere lagoons, and Saltwater creek wetland system repair sites

  • Field surveys here will continue to generate water ecology, plant assessment, hydrology and water quality knowledge. We plan to deploy high frequency loggers to track water quality conditions, take spot measurements for nutrients and turbidity, in addition to complete aquatic flora and fauna surveys. These data will place us in a strong position to evaluate management treatments administered, and determine connectivity (i.e. evaluating estuarine and freshwater connection) with downstream marine habitats (diadromous aquatic species). These data will inform future wetland repair projects, to ensure maximum benefits are achieved for funding available;
  • Field trials to understand nutrient content and removal efficacy of freshwater invasive aquatic plant species.  Efforts to mechanically remove invasive aquatic plants are expensive, and while this probably reduces nutrients from wetland systems after removal water treatment of new water flow has been lost.  Here we will examine whether selective harvesting of aquatic plants achieves better water quality outcomes.

New project partners – Bundy Sugar (Littabella wetland) and Pacific Reef Fisheries (Kalamia estuary/freshwater aquatic weeds)

  • Littabella wetland – this wetland reserve is impacted by cattle and a road cause-way which limits tidal exchange to the upper wetland margins. Here field surveys here will cover water ecology, plant assessments, and water quality. We plan to deploy high frequency loggers to track water quality conditions, take spot measurements for nutrients and turbidity, in addition to complete aquatic flora and fauna surveys. These data will place us in a strong position to evaluate management treatments administered, and determine connectivity (i.e. evaluating estuarine and freshwater connection) with downstream marine habitats (diadromous aquatic species);
  • Kalamia estuary – Pacific Reef Fisheries is an aquaculture operation near the mouth of Kalamia estuary, Burdekin. This operation has a licence to extract saltwater for their operation. The upper estuary is currently suffering from the spread of invasive freshwater plant species, presumably because of the freshwater delivery through the upstream distribution network, and leaking infrastructure. Here we will deploy high frequency loggers to measure water conditions, and depth, to calculate the tidal regime necessary to reach the upper estuary to destroy invasive freshwater plants. This project requires a balance between tidal regime necessary to reach the upper estuary and the aquaculture facility needs.

Prepare case studies using Values Based Causal Framework

  • The Queensland Wetlands team recently prepared a values based causal framework that serves to capture wetland system repair data for project sites and present information in a consistent and meaningful way to demonstrate the ecosystem values to be protected, drives of pressures, components and processes impacting the project outcome and monitoring and evaluation necessary. Integrating data generated in Project 3.3.2 and this project will support directly the Queensland Wetland team to convey information, allowing other NRM and community groups to assess project success and risks before commencing. Preparing these case studies using this framework will be a first for Queensland, and Australia. This framework and case studies will be widely utilised by wetland scientists, policy, community and managers across Australia.

Links with other projects and hubs

  • NESP Tropical Water Quality Hub – Project 2.1.2 Cane land transition and wetland repair (completed May 2017)
  • NESP Marine Biodiversity Hub – Project B4 – Underpinning the repair and conservation of Australia’s threatened coastal-marine habitats (completed 2015)
  • NESP Tropical Water Quality Hub (proposal in current funding round) – Priority 1D – Innovative approaches for using economic levers for achieving nutrient/sediment loss reductions and/or to encourage land use or practice change
  • NESP Tropical Water Quality Hub – Project 3.1.4 – Optimising the management of riparian zones to improve the health of the Great Barrier Reef (commencing January 2017)
  • NESP Tropical Water Quality Hub – Project 3.3.2 – Science evaluation of wetland system repair project sites in GBR catchments (commencing January 2017).

Management outcomes in this project include

  • Key project partners have direct input in the experiment design, data interpretation and reporting of results – maximising end user adoption of the results and conclusions;
  • Scientific evaluation and data to provide surety and confidence that investment into system repair projects via the state and federal government programs has delivered an acceptable return on this investment;
  • Through this science program, end user members involved will gain skills to continue evaluation of future wetland projects, and the confidence to alter programs as necessary – achieving end user adoption and change management;
  • Consolidation and evaluation of coastal wetland system repair projects across the GBR catchment area, to examine cross learnings, with the data to be provided into a database in Queensland Government (WetlandInfo);
  • Evaluation of a range of wetland system repair projects completed or underway to improve the environmental and cost effectiveness of future wetland system repair efforts (for example those under priority 1D – economic levers and schemes);
  • Delivering exchange of knowledge between scientists, NRM (NQ Dry Tropics, Burnett Mary Regional Group), Jaragun Natural Resources Management group staff, to evaluate restoration works and report on the outcomes; and
  • Scientific publications, media releases, community presentations and technical report.

Achieved outputs (so far) in NESP TWQ Project 3.3.2

Social and print media

Numerous articles have been prepared and released via NESP TWQ, RRRC, and JCU.


A project factsheet has been prepared for the project, in addition to a poster that was shown at the National Science week display in DOEE.  Factsheets have been also generated by project partners, most recently NQ Dry Tropics generated a “Connecting Cane Farmers to Wetlands” factsheet, that featured data emerging from NESP Project 3.3.2.

Industry linkage

The constructed wetland in Babinda with Jaragun NRM has received considerable media and industry attention.  Most notably are Green Collar and the Reef Credits program, where Jaragun NRM are likely to secure industry funding to extent their program, which has been supported by the data generated during Project 3.3.2.


  1. Buelow, C., Waltham N. (2018) Functional role of freshwater bivalves in filtration of agricultural nutrient runoff delivery to coastal floodplain (Submitted August 2018, Water Research)
  2. McCann, D., Owen, L., Waltham N (2018) Design of Babinda constructed wetland in the wet tropics of the GBR. Stormwater 2018 conference (Submitted August 2018)
  3. Adame, MF, Rodriguez, S, Franklin H, Kavehei E, Turschwell M, Balcombe S, Kaniweska P, Burford M, Waltham N, Ronan M (Submitted August 2018) Nitrogen removal by tropical forested wetlands through denitrification. Marine and Freshwater Research
  4. Adams, F, Arthington A, Waltham NJ, Amelia, Ronan M, (Submitted May 2018) Wetlands of the GBR: conditions and challenges for future protection. Aquatic Conservation: Marine and Freshwater Research


  • Estuarine Coastal Sciences Association Conference (September 2018)
  • Presentation to NESP TWQ steering committee (June 2018)
  • Presentation to DOEE (June 2018)
  • Presentation to Queensland Wetland Governance Committee (July 2018)
  • Presentation to WTMIPs (June 2018)
  • Presentation to NQ Dry Tropics Board (August 2018)
  • Green Collar presentation – Wetland working group (February 2018)
  • Article in CaneGrowers (October 2016)


NESP 2017 Research Priority Alignment

Theme 1 – Improved understanding of the impacts, including cumulative impacts, and pressures on priority freshwater, coastal and marine ecosystems and species

This project directly delivers data and knowledge to end users on the impacts of land use change on coastal wetlands, and how projects aimed at restoring and repairing wetlands achieve the objectives.  This project includes a large range of end users that are involved in projects from day one, and continually assist with generation of data and information.  This NESP project, like our previous projects, will continually promote the results and achievements made by project partners.

Theme 2 – Maximise the resilience of vulnerable species to the impacts of climate change and climate variability by reducing other pressures, including poor water quality

This project will provide data and information to assist end users continually improve and refine wetland system repair projects, so to maximise resilience of vulnerable species and water quality in wetlands to external drivers.  In some project sites, we plan to combine field surveys with laboratory experiments as a way directly examine like consequences of future changes, such as climate, on wetland repair projects.

Theme 3 – Natural resource management improvements based on sound understanding of the status and long-term trends of priority species and systems

This is the most relevant research theme to this project.  The large number of project partners ensures management improvements and decisions are supported by sound understanding of status and long-term trends.  This outcome is critical, as the learnings here must be transferable to other end user groups that might consider similar restoration approaches in local settings – ensuring future projects don’t repeat mistakes and maximise the outcomes for the funding investment.


Project Keywords

Water quality; Wetland system repair; Biodiversity; Ecohydrology; Indigenous engagement.


Project Funding

This project is jointly funded through JCU, GU, UQ, Queensland Government – Wetlands Program, NQ Dry Tropics, Jaragun Pty Ltd and the Australian Government’s National Environmental Science Program.