Maroochy Groyne field renewal project

The entrance to the Maroochy River migrates due to coastal and estuarine processes. Its location has been both north and south of Pincushion Island since the 1940’s.

Project scope

Following the successful Stage 1 Maroochy Groyne renewal and seawall works in August 2020, Stage 2 works will take place from early-May to late-September 2022:

Stage 1 included replacing the two northern-most Groyne structures and part of the existing seawall surrounding the Cotton Tree Holiday Park
Stage 2 works includes replacing the two remaining Groyne structures and extending the existing seawall to further protect the foreshore.

The replacement Groynes and seawall are constructed using sand-filled geotextile containers (also known as geobags or geofabric bags) and protect the Cotton Tree precinct from the current and future impacts of coastal erosion.

Construction schedule

Zone 1 - Groynes #1 and #2 reconstruction (early-May - mid-July 2022)

Deconstruction of existing deteriorated sand-filled geotextile container Groynes
Construction of new sand-filled geotextile container Groynes - including supply, filling and placement of sand containers.

Zone 2 - Extension of existing seawall (*early-July - late-September 2022)

Construction of new sand-filled geotextile container seawall extension - including supply, filling and placement of sand containers.

*Exact timing of the seawall extension is subject to lodged development application approval and will be confirmed as soon as possible.

Community access will be maintained to the Cotton Tree Holiday Park, beach and river in dedicated ‘safe zones’ during construction. Some areas of the beach will be temporarily fenced off and temporary swimming exclusion zones will apply.

Emergency vehicle access will remain to the beach.

The Surf Life Saving camera will continue to operate.

To help progress the works as safely and quickly as possible a section of the Alexandra Parade beach car park will be temporarily closed and used by the construction contractor. Approximately 50% of the car park will remain available for community use.

Environmental controls

As was the case with stage 1, stage 2 is being undertaken with all relevant environmental permits in place. At times, water surrounding the groyne may seem discoloured due to sand disturbance. There is no cause for alarm and water quality monitoring will be in place.

Sand used to fill the new geotextile bags will be sourced directly adjacent to the works site, with the sand from the old bags reclaimed and used to replenish the beach.

Where to from here

Council is committed to keeping residents and businesses informed about ongoing works. View the latest project news (PDF, 617KB).

Register to receive regular construction updates via email. Please include your details (name, address and email address).

Background

Southern migration in the 1990’s saw erosive pressure occur at the Cotton Tree Holiday Park.

In 2003 council constructed the Groyne and sections of seawall to help protect the Cotton Tree Holiday Park and other nearby valuable assets. Some of the existing Groyne structure has now deteriorated and needs to be replaced.

Renewal of the Maroochy Groyne will ensure ongoing protection of the Cotton Tree precinct from erosion.

This renewal project is the result of extensive council planning, including a 10-year Shoreline Erosion Management Plan (SEMP) developed in 2014. This plan and the Groyne renewal project incorporate sound science, coastal engineering principles, physical modelling, community values and coastal dynamics.

Community engagement

Council undertook extensive community consultation when considering options for the Groyne renewal in 2017. This included establishing the Maroochy River Estuary Consultation Group (which has continued to work with council on design options and testing) and seeking wider community feedback.

Council considered this feedback in determining that the existing Groyne would be replaced with geotextile bags instead of rock. This consultation was recognised nationally with a 2019 Australian Coastal Award for Community Engagement.