Scientists paint harbour pink 

Pink dye is released into Darwin Harbour. (ABC TV)

A research project tracking the flow of waste from sewerage outlets saw seawater in Darwin Harbour turn pink over the weekend.

A rose-coloured plume stretching for about half a kilometre was visible as scientists from Charles Darwin University took to the water for the tidal study.

The study, a partnership between CDU, Power and Water, and the Australian Nuclear Science and Technology Organisation, will support the move to expand the existing Darwin sewage plant so it can close the Larrakeyah outfall.

Internationally recognised expert and CDU's Professor of Civil Engineering, Eric Valentine led the project and has been working extensively with Power and Water in the design of the new outfall.

“The team poured some 50 litres of pink-coloured rhodamine into the East Point seawater to determine where the tide carries waste water it pumps into the harbour,” he said.

Tracers were released into the water about 1km from East Point and then monitored by the team of scientists from boats and a helicopter.

“While computer modelling shows rapid dispersion of treated wastewater due to tides in Darwin Harbour, this study will calibrate that model and help determine the best location for the outfall,” Professor Valentine said.

The outcomes of the study will be incorporated into a Public Environment Report that should be completed by the end of this year.