21 February 2023
Climate change and population growth are accelerating the need for diverse solutions to coastal protection. Traditionally, shorelines are armoured with conventional ‘hard’ engineering structures such as seawalls which need ongoing maintenance and upgrades. While hard structures will continue to have a place in coastal protection, alternative methods known as ‘living shorelines’ can be more sustainable and climate-resilient.
Living shorelines harness natural ecosystems to reduce coastal erosion and flooding, and provide co-benefits such as carbon sequestration. They may consist of dunes, wetlands and biogenic reefs: either alone (soft approach) or together with hard structures (hybrid approach). Land managers and community groups engaged in shoreline restoration can benefit greatly from a national repository of learnings from existing projects.
Australia’s first living shorelines database is a starting point to upscaling the use of living shorelines as standard practice for coastal hazard risk management. Living Shorelines Australia was developed by University of Melbourne in a project funded by the Australian Government under the National Environmental Science Program Marine and Coastal Hub. It showcases examples and experiences, sharing knowledge to help practitioners tackle major barriers associated with living shorelines implementation.
The online database contains 138 projects identified though a survey, a literature review and other sources. Most projects involve beach or dune management, with mangrove-based living shorelines being the next most common approach. Soft approaches were more common than hybrid approaches, except for those including mangroves and shellfish reefs.
For example, at Scott’s Point in New South Wales, rock fillets were installed along a kilometre of coastline to dissipate water movement and allow mangrove re-establishment on the banks of eroded riverbanks. Dense trees, shrubs and ground cover plants were planted leading to natural regeneration of mangrove and saltmarsh species and restabilisation of the banks.
At Holdfast Bay in South Australia, a 3.6 hectare area of eroded dunes was sand-fenced and replanted to restore the primary dune structure and swale. At Portarlington, Victoria, an artificial shellfish reef was installed 100 metres from shore to resemble a breakwater, leading to decreased inundation events, increased sand accumulation, and re-establishment of seagrass in the shallow waters.
The project survey also identified various barriers to implementation. These include a lack of understanding, expertise and sample projects, uncertainty in the level of risk reduction, and planning and regulation. Actions needed to support implementation include developing technical guidelines, demonstration projects and emerging technologies, and co-design with a diversity of community groups.
The Living Shorelines Australia website also provides The Australian guide to nature-based methods for reducing risk from coastal hazards, a report of the Earth Systems and Climate Change Hub and the National Centre for Coasts and Climate.