Wetlands play a huge role in coastal protection.
From seagrass meadows and salt marshes to freshwater swamps and mangrove forests, wetlands are diverse ecosystems that protect our coastlines, filter water pollution and store carbon. Wetlands help reduce the impacts of extreme weather events such as floods and cyclones, saving Australians hundreds of millions of dollars in damage each year.¹ They filter out pollutants before they reach the ocean and lock away carbon, helping to combat climate change.
Historically, wetlands have been cleared for housing, farming and industry. Protecting and restoring them today is a smart, cost-effective solution to strengthen the resilience of our coastal communities, ecosystems and the Reef.
How can wetlands help protect coastal communities from extreme weather?
Extreme weather events threaten our communities as they become more frequent and intense due to climate change. Wetlands are an effective natural defence against the impacts of extreme weather like flooding, storm surges, and cyclones.
How can wetlands reduce flooding?
Think of wetlands and their plants like reservoirs and sponges that absorb rain, slow water flow and reduce the risk of flood damage.
Wetlands in floodplains are a great example of these processes. These low-lying areas, like those adjacent to the Pioneer and Plane rivers in Mackay-Whitsundays, are meant to flood. When rivers overflow, water spreads across the floodplain, forming wetlands that can store large volumes of water. Plants that grow in and alongside wetlands also absorb and store rainfall in their tissue.² This helps reduce the speed and volume of floodwaters and pollutants moving downstream. As water levels recede, water is slowly released from the floodplains back into the rivers.³ ⁴
The opposite occurs when wetlands are cleared and river channels straightened for development. Floodwaters disperse more quickly into our communities, farmland and coastal ecosystems.⁵ More than half the suburbs in Mackay are susceptible to flooding from the Pioneer River, where 84% of wetlands have been cleared.⁶ Besides threatening people’s livelihoods, floods carry large amounts of pollutants into the ocean and our Great Barrier Reef.
Restoring and protecting floodplains and wetlands has the benefit of building safer, more resilient communities and healthy ecosystems.⁷
How natural floodplains and wetlands protect communities from flooding by @PaulieJTails
How can wetlands reduce the impacts of cyclones?
Wetlands help protect our coastlines from cyclone impacts. Cyclones can generate powerful waves and storm surges that threaten buildings, houses, ships and fishing boats.⁸ Healthy wetlands help absorb the energy of waves and storm surges, reducing the impacts of cyclones on our coastal communities. ⁹ ¹⁰ The dense vegetation of coastal wetlands, like mangroves and salt marshes, also reduces erosion by stabilising the soil with their roots. ¹¹
While seawalls and bulkheads are often used to protect coastlines, this artificial infrastructure is costly to build and maintain and has a limited lifespan. In contrast, wetlands offer coastal protection that is cost-effective, long-lasting, and can support biodiversity.¹²
Wetlands reduce water pollution from flooding
Wetlands remove waterborne pollutants as they are carried downstream during flood events. The plants growing along rivers and streams slow surface water and fix the soil, which leads to less sediment entering the ocean, where it can block essential sunlight and smother corals and seagrass.¹³ ¹⁴
Our coastal ecosystems are also threatened by high levels of dissolved inorganic nitrogen entering rivers and streams, mostly from fertiliser washed off farms. When excessive nitrogen reaches the ocean, it reduces the growth, reproduction, and survival of corals and seagrasses.
Healthy wetlands with native vegetation can remove nitrogen from the water with the help of bacteria that consume nitrogen.¹⁵ Coastal wetlands in tropical Queensland have the potential to remove 70% of nitrate (a form of nitrogen) during the first 24 hours of a flood.¹⁶
Why are wetlands at risk?
Despite their importance, wetlands are one of the most threatened ecosystems globally. In the Great Barrier Reef catchment alone, more than half of the natural wetlands have been cleared.¹⁷ While the loss has slowed since 2017, in the years prior, over 557 hectares of coastal wetlands and at least 1000 kilometres of vegetation along rivers and streams leading to the Reef were cleared for agricultural, industrial, and urban purposes.¹⁸ More frequent and intense extreme weather events as a result of climate change are accelerating the loss and degradation of valuable wetlands.¹⁹
The economic benefit of wetlands
Recovery costs from extreme weather events are expected to rise against a backdrop of climate change. We need the protection of our coastal wetlands more than ever.
Queensland is the most disaster-prone state in Australia, with extreme weather events causing damage worth $18.2 billion per year.²⁰ Flooding in North Queensland in 2019 and Tropical Cyclone Jasper in December 2023 caused a combined economic loss of over $6.3 billion, impacted thousands of homes, agricultural land and livestock across the region.²¹ ²²
Examples of wetlands providing economic benefits:
- Wetlands prevent an average of $236 million in damage per storm. With over 200 tropical cyclones recorded to date along Queensland’s east coast, wetlands may have saved us over $48 billion.²³
- Healthy wetlands can reduce flood-related costs by up to 38%.²⁴ In 2020–21 alone, mangroves protected more than 4,000 coastal homes in Australia, preventing over $57 million in damage.²⁵
Restored wetlands are a long-term solution
If we want more resilient communities and coastlines, we must prioritise wetland restoration as a form of coastal protection.
Successful restoration projects in the Florida Everglades, London’s Thames River and the Yangtze River in China show that the impacts of extreme weather events can be reduced on coastal communities and ecosystems.²⁶ ²⁷ ²⁸
Restoring wetlands is also an effective long-term strategy to cut water pollution.²⁹ Restoring just 5% of a land parcel can reduce nitrogen pollution entering the coastal zone by 20 to 50%.³⁰
Restored wetlands provide many other ecosystem services, from increasing biodiversity, absorbing large amounts of carbon from the atmosphere and providing tourism and recreational opportunities. The combined value of restored wetlands far outweighs the cost of restoration projects, making them a cost-effective, complementary solution to address water pollution and protect our coasts.³¹ ³²
What you can do to help protect wetlands
Healthy wetlands not only protect our coastal and marine ecosystems, but also the jobs and communities that depend on them.
Individuals and communities can urge politicians and governments to fund and deliver more wetland restoration by signing petitions, talking to local politicians and advocating publicly for wetland restoration. They can volunteer with local organisations undertaking restoration projects or donate to organisations to support their work.
References:
Australian Bureau of Statistics. (2025). National ecosystem accounts, experimental estimates. Retrieved April 9, 2025, from https://www.abs.gov.au/statistics/environment/environmental-management/national-ecosystem-accounts-experimental-estimates/2020-21
Queensland Government, Department of Environment, Science and Innovation. (n.d.). Riparian vegetation. WetlandInfo. Retrieved from https://wetlandinfo.des.qld.gov.au/wetlands/ecology/components/biota/flora/flora-structural/riparian-vegetation.html
Ramsar Convention Secretariat. (2001). Wetland ecosystem services. Retrieved from https://www.ramsar.org/sites/default/files/documents/library/services_01_e.pdf
Queensland Government, Department of Environment, Science and Innovation. (n.d.). Flooding. WetlandInfo. Retrieved from https://wetlandinfo.des.qld.gov.au/wetlands/ecology/processes-systems/flooding/
Department of Environment, Science and Innovation, Queensland. (2023). Wetlands and disaster management. WetlandInfo. Retrieved March 4, 2025, from https://wetlandinfo.des.qld.gov.au/wetlands/management/disaster.html
Queensland Government, Reef Water Quality Protection Plan. (n.d.). Mackay–Whitsunday region report. Retrieved from https://www.reefplan.qld.gov.au/__data/assets/pdf_file/0014/46103/mackay-whitsunday-region.pdf
Ramsar Convention Secretariat. (2022). Wetlands and disaster risk reduction (Fact sheet 9). Retrieved from https://www.ramsar.org/sites/default/files/fs_9_drr_eng_22fev.pdf
Bureau of Meteorology. (n.d.). Understanding storm surge. Tropical Cyclone Knowledge Centre. Retrieved from http://www.bom.gov.au/cyclone/tropical-cyclone-knowledge-centre/understanding/storm-surge/
Mulder, O. J., Mulder, K. P., Kubiszewski, I., Anderson, S. J., Costanza, R., & Sutton, P. (2020). The value of coastal wetlands for storm protection in Australia. Ecosystem Services, 46, 101213. https://doi.org/10.1016/j.ecoser.2020.101213
Ramsar Convention Secretariat. (2022). Wetlands and disaster risk reduction (Fact sheet 9). Retrieved from https://www.ramsar.org/sites/default/files/fs_9_drr_eng_22fev.pdf
Department of Environment, Science and Innovation, Queensland. (2023). Wetlands and disaster management. WetlandInfo. Retrieved March 4, 2025, from https://wetlandinfo.des.qld.gov.au/wetlands/management/disaster.html
Ouyang, X., Lee, S. Y., Connolly, R. M., et al. (2018). Spatially-explicit valuation of coastal wetlands for cyclone mitigation in Australia and China. Scientific Reports, 8, 3035. https://doi.org/10.1038/s41598-018-21217-z
Queensland Government, Department of Environment, Science and Innovation. (n.d.). Riparian vegetation. WetlandInfo. Retrieved from https://wetlandinfo.des.qld.gov.au/wetlands/ecology/components/biota/flora/flora-structural/riparian-vegetation.html
Reef 2050 Wetlands Strategy. (n.d.). Reef 2050 Wetlands Strategy. Queensland Wetlands Program.
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Adame, M. F., Roberts, M. E., Hamilton, D. P., Ndehedehe, C. E., Reis, V., Lu, J., Griffiths, M., Curwen, G., & Ronan, M. (2019). Tropical coastal wetlands ameliorate nitrogen export during floods. Frontiers in Marine Science, 6, 671. https://doi.org/10.3389/fmars.2019.00671
Queensland Government. (n.d.). Queensland Wetlands Program. Retrieved from https://www.dcceew.gov.au/water/wetlands/wetlands-programs/queensland-wetlands-program/great
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Reef 2050 Wetlands Strategy. (n.d.). Reef 2050 Wetlands Strategy. Queensland Wetlands Program.
Queensland Reconstruction Authority. (2023). State Disaster Risk Report 2023. Retrieved from https://www.disaster.qld.gov.au/__data/assets/pdf_file/0020/436070/2023-State-Disaster-Risk-Report.pdf
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Mulder, O. J., Mulder, K. P., Kubiszewski, I., Anderson, S. J., Costanza, R., & Sutton, P. (2020). The value of coastal wetlands for storm protection in Australia. Ecosystem Services, 46, 101213. https://doi.org/10.1016/j.ecoser.2020.101213
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Waltham, N. J., Wegscheidl, C. J., Smart, J. C. R., Volders, A., Hasan, S., & Waterhouse, J. (2017). Scoping land conversion options for high DIN risk, low-lying sugarcane, to alternative use for water quality improvement in Wet Tropics catchments (141 pp.). Reef and Rainforest Research Centre Limited, Cairns.
Adame, M. F., & Kavehei, E. (2021). Ongoing efficiency of nitrogen processing in treatment wetlands of the Wet Tropics (ARI Report No. 2021/004). Australian Rivers Institute, Griffith University, Brisbane.
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