Standard Presentation Australian Marine Sciences Association Annual Meeting 2023

Mangrove living shorelines for erosion mitigation and their resilience to flooding (#159)

Sophie C. Y. Chan 1 , Stephen E. Swearer 1 , Rebecca L. Morris 1
  1. National Centre for Coasts and Climate, School of BioSciences, The University of Melbourne, Victoria, Australia

Coastal development and increasing coastal hazards have intensified coastal erosion globally. Living shorelines have been increasingly tested as a more adaptive option for coastal hazard protection than the traditional artificial structures under climate change. Living shorelines incorporate coastal habitats to enhance structural complexity and restore ecological functions. In New South Wales, Australia, rock and timber fillets were installed to reduce wave energy and facilitate sediment accumulation and mangrove establishment along eroding shorelines. A chronosequence of mangrove living shorelines in Hunter River and Manning River, ranging from three to 12 years were evaluated for their effectiveness at mangrove recruitment and erosion mitigation. Between 2019 and 2022, these shorelines experienced severe flooding. Using historical aerial imagery, we compared rate of bank lateral erosion before-after installation and between living shorelines and bare shorelines, and their resilience to flood events. Mangroves have successfully established in most living shorelines but their effectiveness at mitigating erosion was site-specific. The protection during flood events was also variable. Differences in geographical and living shoreline designs may influence their effectiveness in reducing erosion.