Sonar used to locate underwater dangers

An advanced sonar program has started surveying NSW rivers for hazardous submerged debris across the State following this year’s destructive floods with shoreline clean-up crews coming in behind to remove those debris once located.

The NSW Environment Protection Authority (EPA)-led program removes dangerous obstacles to navigation and water safety – including giant tree trunks and water tanks – out of our rivers.

EPA Director Arminda Ryan said the Sonar (submerged debris) Clean-up Program was uncovering submerged and dangerous debris washed into the Hawkesbury and other rivers during the recent floods.

“By using the latest technology available our aim is to make this recovery as thorough and efficient as possible,” Ms Ryan said.

The strength of the Sonar Program is its ability to reveal otherwise invisible hazards. Sonar Technology mounted on boats sends out sound waves and measures returning echoes to detect large items on the riverbed. 

Based on what has been found on shoreside clean-ups hazards are expected to include items as diverse as chemical drums, farming equipment, large tree branches and even caravans.

Ms Ryan said the Sonar Program was just one part of a combined NSW Government agency effort with the EPA working closely with Transport for NSW to secure and mark hazardous debris prior to removal.  

“Transport for NSW has provided the EPA with 11 priority locations for surveying in the Hawkesbury River. OceanWatch Australia have provided a further two priority locations. Transport for NSW will also provide priority locations for surveying on the North Coast,” Ms Ryan said

“The program covers a broad area and will see a wide variety of man-made and natural hazardous debris removed from waterways extending from the Hawkesbury River to the Queensland border.”

Ms Ryan said the shoreline clean-up had already removed more than 6800 cubic meters of eligible flood debris across NSW since the beginning of March, which is more than 340, 8-tonne tip trucks.

“The communities in flood impacted areas have been through very tough times in the past couple of years and the extension of these programs will support communities with their recovery from the floods,” Ms Ryan said.

“These clean-ups will take time and we ask people to remain patient but also to be safe around the water if they are assisting with clean-up or using local beaches and waterways.” 

The EPA was able to move quickly on this work to help communities recover from the devastating floods and extreme weather of this year by extending flood recovery programs that were already underway following the 2021 floods – like the Sonar Program.

Members of the community can assist the clean-up of their local area by reporting flood debris to the Environment Line on 131 555 or