Sunshine Coast Council has completed the first stage of work to help maintain and protect the Cotton Tree coastline from erosion.
Stage one works on the Maroochy Groyne Renewal Project started in April 2020. More than 1800 geotextile containers filled with sand—also known as geobags—were used to build a seawall and two groynes which will interrupt wave action, capture sand and provide an erosion buffer.
The largest of the geobags are filled with 11 tonnes of sand—about the weight of eight cars.
Stage one of the project focussed on renewing the northern-most groyne structures near the Cotton Tree Holiday Park.
Stage two of the project is scheduled to take place in 2021 and will focus on the two southern-most groyne structures (Groyne #1 and #2).
Sunshine Coast Council Coastal Engineer Georgia Keeshan said geobags were placed in the area around 2003 after the Maroochy River entrance migrated south in the late 1990s.
“The entrance to the river naturally migrates due to coastal and estuarine processes.
“Structures that were in place to address the erosion require maintenance from time to time to continue to provide protection,” Ms Keeshan said.
Council worked closely with industry specialists including researchers, geobag manufacturers and engineers from the Water Research Laboratory at the University of New South Wales to develop and test the structures prior to use.
“We are pleased to have had the opportunity to work with the research specialists to develop an innovative and effective way to protect the much-loved Cotton Tree precinct,” Ms Keeshan said.
Ms Keeshan said the sand used to fill the new geobags was sourced adjacent to the work site and the sand from the old geobags was used to replenish the beach.
Division 8 Councillor Jason O’Pray said the project had been a long time in the making and was part of council’s 10-year Shoreline Erosion Management Plan.
“Protecting this stretch of coastline and the cherished Cotton Tree precinct is a great achievement and the result of extensive council planning and community consultation,” Cr O’Pray said.
“I feel extremely proud to have been a part of the project from inception and was thrilled to see the final geobag being placed this week.”
Division 4 Councillor Joe Natoli thanked the community for their ongoing support.
“Community input played a significant role in the successful delivery of this project,” Cr Natoli said
“I would like to acknowledge everyone who contributed, including the Maroochy River Estuary Consultation Group.”