Council is commencing an environmental assessment process and developing a concept design for the Merimbula Sewerage Treatment Plant (STP) Upgrade and deep water ocean outfall and the testing is critical to the hydrodynamic modelling for the project.

Council’s water and sewerage services manager, Jim Collins, said council is acting on advice from the NSW Environment Protection Authority and also local community concerns, that the existing beach-face outfall at Merimbula STP is not sustainable.

“The information we receive from these tests will show the dispersion rates and travel times of waterborne materials in the bay, and will help our designers determine the best location for the placement of the deep water ocean outfall,” Mr Collins said.

“The process will involve council’s consultant hydrologists releasing a harmless, bright red fluorescent dye called Rhodamine into the water at up to four locations in the Bay, including Haycock Point (east and north) and Merimbula Embayment.  

Mr Collins said Merimbula Bay will be open and safe for all water users during the tests.

“Rhodamine, which will disperse rapidly, follows the pathways of currents closely and has a low impact on water quality. It will be used to measure how long it takes the currents to move water between predetermined sampling sites, with the testing set to take a few hours in each location,” Mr Collins said.

The project is in the very early stages.

It is expected to cost in the region of $30m and would require government funding. Council said in the coming weeks a website would be launched to provide more information on the project and how the community would be able to provide feedback and get involved.