OzSET: Integration and publication of the Australian Surface Elevation Table dataset

PROJECT 1.11

Australia’s coastal floodplains and wetlands provide essential ecosystem services and have immense cultural value. They regulate water quality, moderate flood and storm damage, and provide habitat for marine life including commercial fish and shellfish species. A national approach is needed to monitor and assess the way coastal floodplains and wetlands are changing in response to environmental changes such as accelerating rates of sea level rise.
A useful measure of resilience is the extent to which coastal wetland sediments can accrete vertically at a rate matching that of sea-level rise. This requires monitoring vertical accretion, subsidence and elevation gain across a range of coastal settings.

The Surface Elevation Table-Marker Horizon (SET-MH) technique and associated instrumentation measures the vertical accretion of coastal wetland sediments. This allows the assessment of whether wetlands are keeping pace with sea level rise (measured at tide gauges) or subsiding relative to local sea level rise and thus vulnerable to permanent inundation and loss. This knowledge can underpin spatial models of the resilience of coastal wetlands to sea level rise, and facilitate coastal planning, estimates of blue carbon sequestration, and potential changes in other ecosystem services.

Australia has an extensive network of surface elevation tables in coastal wetlands. The majority were installed in 2000–2001, funded by state and local government agencies seeking better information on the resilience of coastal sedimentary environments to sea-level rise. They have been maintained by Marine and Coastal Hub partners including Macquarie University, University of Wollongong, University of Queensland, University of Adelaide, Charles Darwin University and Edith Cowan University. The data they gather, however, are not readily available to the research community or research users.

Understanding the impacts of sea level rise and coastal wetland resilience

This project will collate existing SET-MH data, provide a meta-analysis and make publicly available a dataset covering a 20-year period of accelerating sea-level rise. The national data platform will enable SET-MH data to be linked to other national data to understand the impacts of sea level rise and coastal wetland resilience.

The data will cover accretion, subsidence and elevation change in mangroves, saltmarshes, seagrasses and tidal freshwater forests. Core data to be collated for each SET-MH installation include:

• rate of sediment accretion: sediment accumulation above the baseline for each measurement period, and the linear trend through time;
• rate of elevation gain: elevation in relation to the benchmark (vertical position at installation) for each measurement period, and the linear trend through time;
• rate of upper level subsidence: difference between the rate of sediment accretion and the rate of elevation gain; and
• elevation deficit: difference between rate of sea-level rise and the rate of elevation gain.

The coordinated SET-MH platform will provide a national resource to monitor the resilience of coastal wetlands with sea level rise and other climate change impacts. These data can be used to validate remotely sensed products, underpin modelling of the impacts of sea level rise on wetland distribution and monitor variation in soil accretion and carbon sequestration over time.

In addition, information on shoreline trends in the vicinity of SET-MH installations will be accessed from Digital Earth Australia Coastlines, a continental dataset that includes annual shorelines and rates of coastal change along the entire Australian coastline from 1988 to the present. The comparison of data will provide insight into processes influencing shoreline change.

Project location

National 

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