The 2017 Gold Coast Beach Nourishment Project experience – Delivering an effective nourishment project through a multi-criteria framework

Mr Gildas Colleter1, Mr Shanon Hunt2

1JBP, Lvel 2, 433 Boundary Street, Spring Hill, Australia, 2City of Gold Coast, Po Box 5042 Gold Coast Mail Centre, Australia

Abstract

Beach nourishment is a key adaptive strategy to address some of the effect related to Climate Change. However, beach nourishment projects are not always “successful”, particularly from an environmental and community perspective. The presentation reviews how including social and environmental values into a nourishment project can improve beach nourishment project outcomes.

During the 2017 Gold Coast Beach Nourishment Project, over 3 million cubic-meters of sand were placed over 10km of beaches, at Palm Beach and from Miami to Surfers Paradise over a short 3 months period.

The City of Gold Coast used a Framework to drive weekly sand placement instructions to the dredge which placed the sand via rainbowing and bottom dumping into the nearshore zone. The placement included both the creation of short-term sand bars and long-term nearshore coastal deposits. These new deposits eventually merged into the upper beach and increased the coastal protection value of the Gold Coast beach.

A decision-making Framework managed the preparation of the weekly sequence of placement to build the project in the most acceptable manner overall. The Framework used a wide variety of data such as bathymetric survey data, LiDAR,  surveys, track-plots, etc. The data considered also surfing crowd observations, population maps, beach assets, natural reefs as well as meteorological forecast. The Framework led to the placement to be performed in a semi-random placement sequence. This provided period of rest for the sand to be mobilized by waves, allowed surfing amenity benefits and avoided long interruptions to beach users.

Undertaking nearshore beach nourishment using offshore sand reserve was proven to be a low environmental harm and low-cost method to manage erosion. The project success also renewed community support for Beach Management.

Biography

Gildas is a  Chartered Professional coastal engineer specialised in the delivery of marine and coastal projects. Gildas has expert knowledge of coastal numerical modelling, physical modelling, ports and coasts studies and marine works design.

Over his 20-year career he had technical leading role in many internationally acclaimed coastal engineering projects including Darwin Waterfront redevelopment, the Barangaroo and Brisbane Ferry Terminals. Gildas directed the 2017 Gold Coast beach Nourishment for the City of Gold Coast.

He has developed and applied coastal research in fields such as  coral reef hydraulics, cyclonic wave-structure interactions, Computational Fluid Dynamics (CFD), LIDAR and Laser Scanner to identify, study, design and manage climate-resilient coastal infrastructure.

About the Association

The Australian Coastal Society (ACS) was initiated at the Coast to Coast Conference in Tasmania in 2004. The idea was floated as a means for those interested in coastal matters to communicate between conferences and where possible take resolutions of the conference to appropriate levels of government.

The idea was discussed further at the Coast to Coast Conference in Melbourne in 2006 and it was agreed that Bruce Thom develop a constitution of a company limited by guarantee that would operate on a national basis.

This plan was accomplished and in 2008 at the Coast to Coast Conference in Darwin the constitution was ratified and an Executive appointed. The company received charitable status in 2011.

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