Adelaide Beach Management Review

A dredge is a floating vessel – of which there are numerous types – specifically designed to collect, transport and place marine sand. Various equipment will be tested during the trial to assess the best methods for dredging and sand placement.

Sand is expected to be dredged from a nearshore zone between North Haven and Taperoo and delivered by dredge or barge to West Beach, where it will be placed in a zone near West Beach Surf Life Saving Club.

The Bluecoast Scientific Review identified strategies for managing sand on Adelaide's beaches. The Independent Advisory Panel reviewed these, alongside community feedback, and advised the government on the next steps, which included further investigations into the feasibility of nearshore dredging for sand recycling. This involved analysing the trial site's suitability, documenting the habitat, and consulting with experts to assess the environmental, social, and operational impacts. The findings indicated a trial of nearshore dredging was warranted to test its feasibility and that the selected site was appropriate.

The dredging trial is expected to run for about 8 weeks and be completed by early November 2024, pending approvals and the availability of dredging vessels.

Up to 90,000 cubic metres (m³) of sand, which is the equivalent of 36 Olympic swimming pools.

Dredging requires a licence from the Environment Protection Authority (EPA), which will assess dredging and placement methodologies, environmental monitoring plans, community engagement and reporting detailed in a project-specific dredge management plan.

Monitoring and evaluation will continue after the trial and will include analysis of the sand refill rate at the nearshore zone between North Haven and Taperoo, sand movement at West Beach and consideration of public disruption. This information will help inform a decision on the suitability of dredging as a long-term sand recycling option.

Groynes and breakwaters were not shortlisted based on the scientific review's assessment that they were not as effective at providing protection, practically or financially feasible to maintain and potentially more intrusive on beach users.

Dredging equipment is expected to operate for about 8 weeks in the nearshore zone between North Haven and Taperoo, where a large volume of sand has accumulated through natural coastal processes. The coastline may recede slightly and this will be monitored before and after the trial. These results will form part of the trial evaluation.

Dredging is not expected to affect access to the northern beaches as the dredge and associated equipment are not on the beach.

Dredging is not expected to affect boat access to North Haven Marina. The Department for Environment and Water (DEW) will work with the Department for Infrastructure and Transport (DIT) to notify marina users about the specific times and duration of the dredging operations and exclusion zones around dredge equipment.

The dredging trial aims to replicate the volume of sand that needs to be recycled every year. The department will place up to 90,000m³ of sand at West Beach in a zone near West Beach Surf Life Saving Club.

The trial is likely to include testing of nearshore and beach placement methods using a split hopper barge and delivery of a sand slurry via a pipeline. Spraying, or ‘rainbowing’, will not be trialled. Details of the placement methods and locations will be approved by the EPA and communicated to the public as the trial progresses.

Access may need to be temporarily restricted during trialling of sand placement on the foreshore to ensure public safety. Any restrictions to access, including specific times, locations and duration, will be communicated to the public as the trial progresses.

Dredging is not expected to affect boat access to West Beach boat harbour. DEW will work with DIT to notify harbour users about the specific times and duration of the dredging operations and exclusion zones around dredge equipment.

To ensure the recommended volume of sand can be delivered by 2030, up to 200,000m³ of quarry sand – the equivalent of 80 Olympic swimming pools – will be delivered by trucks to West Beach over the next 12 months. The department will also investigate the option of restoring West Beach by dredging offshore sand. If sufficient suitable sand is found, the department will seek approval to complete the restoration of West Beach with the alternative sand by 2030.

The trial zones have been selected as they are close to the shore where seagrass is not present. The EPA requires a buffer zone between equipment and seagrass to minimise any potential effects. A water quality monitoring plan and seagrass monitoring plan are required before, during and after the dredging trial. If EPA trigger values are exceeded during dredging, mitigation actions, including stopping dredging, will be required.

Marine mammal monitoring is required to be undertaken by the dredge operator and any sightings of dolphins, whales, seals and sea lions must be recorded, including their behaviour. If marine mammals enter the exclusion zone, dredging must stop until they leave.

Regular seafloor surveys will be undertaken during the dredging trial to monitor the rate at which sand refills the dredged area. The underwater placement site at West Beach is expected to return to normal within one to two days via natural coastal processes redistributing the sand.

The decision to proceed with a dredging trial is based on the outcome of the Adelaide Beach Management Review, which included a scientific review of available sand management approaches and comprehensive public consultation. A total of 706 people provided feedback on the scientific review’s shortlisted options, in addition to 39 written submissions and 26 panel hearings. The Adelaide Beach Management Review Independent Advisory Panel recommended further investigations be undertaken to determine the feasibility of recycling sand via nearshore dredging. The department will continue to inform the public as details of the trial are determined and will receive feedback during, and undertake public consultation after, the dredging trial.

Stage 1 results can be found here:

• (Part A) Adelaide Beach Management Review - Stage 1 Engagement Summary Report
• (Part B) Adelaide Beach Management Review - Stage 1 Engagement Summary Report.

Stage 2 results can be found here:

• (Part A) Adelaide Beach Management Review - Stage 2 Engagement Summary Report
• (Part B) Adelaide Beach Management Review - Stage 2 Engagement Summary Report.

$20.7 million has been approved in the 2024-25 State Budget for DEW to deliver:

• A trial of recycling sand by nearshore dredging to determine the feasibility of this approach as an alternative longer-term solution to a sand-pumping pipeline.
• Delivery of about 100,000m³ of quarry sand to West Beach.
• Further investigations to identify and explore the viability of offshore sand sources as an alternative to quarry sand to restore West Beach.
• The continued replenishment of West Beach and erosion hotspots, including Henley Beach South, up to a total of 100,000m³ while the Adelaide Beach Management Review works are completed.

For more information, contact the department on (08) 8124 4928 or at DEW.ABMRImplementation@sa.gov.au