Miss Joanna Garcia-Webb¹, Ms Astrid Stuer¹, Ms Linda Rijkenberg¹

¹Water Technology, Adelaide, Australia

The township of Aldinga Beach is fronted by elevated coastal cliffs along the length of the town. Despite their elevation, the township is subject to increasing social, environmental and economic vulnerability due to ongoing erosion of the cliffs. This study assessed a range of cliff toe protection options to enable Onkaparinga City Council to implement the most appropriate erosion protection works for a section of the cliff.

The options are as follows:

– Option 1: Rock seawall located at the cliff toe

– Option 2: Rock breakwater offset from the cliff, acting to reduce energy at the toe of the cliff without resting directly against the cliff face

– Option 3: This option is a hybrid of Option 1 and Option 2.

— It aims to eliminate the disadvantages of both Options 1 and 2. It incorporates the use of the lower risk offset bund throughout the areas of steeper cliff, whilst at either end of the seawall, where the cliff is less steep and prone to failure, a transition to the seawall approach is employed. This hybrid option saves cost and material from Option 2 whilst also not increasing the risk of working directly adjacent to steep cliffs.

When analysing options, it is important to consult all relevant stakeholders. This presentation will provide an overview of the options and adjustments incorporated into the design to ensure the best possible outcome for all stakeholders.

Biography:

Joanna is a principal coastal engineer with over 15 years’ experience. She is passionate about sustainable management of the coastline. She is particularly interested in coastal processes assessments, design of coastal management solutions and assisting local and state governments with coastal planning and management within the context of relevant state coastal policies. She has extensive experience in numerical modelling of waves and hydrodynamics, and has applied these in numerous studies.

Joanna enjoys working with the community to raise awareness of coastal management and climate change. Joanna places high value on working collaboratively with internal and external stakeholders to achieve project success.