Cooperating with industry to better predict dredging sediment plumes

Much of the research being conducted through WAMSI’s $19 million Dredging Science Node is delivering benefits to industry as well as regulatory agencies and the marine environment. Some of the field work requires close cooperation between researchers and those conducting active marine dredging operations in the Pilbara.

Dr Graham Symonds from CSIRO leads the multidisciplinary WAMSI research team investigating the characteristics of sediment plumes generated by dredging operations associated with the Chevron-operated Wheatstone Project near Onslow. The ultimate objective of the research is to improve predictions of the zones of impact, and to provide the datasets necessary to map ecological responses for future dredging operations.

“Our two periods of fieldwork to date have been good examples of two-way cooperation,” said Graham.

“Chevron and the port authorities were very accommodating in terms of where we needed to collect samples and data during active dredging operations.”

The team used a number of different methods and instruments to look at what was actually happening in the water column in the area around dredging operations.

“We collected samples and data about sediment size and characteristics at a wide range of different depths and locations using a diversity of instrumentation,” said Graham. “In addition, another WAMSI project led by Dr Peter Fearns from Curtin University made ground-truth observations that will help improve the accuracy with which sediment plumes can be monitored by satellite.”

“The staff at the Port of Ashburton – the guys who actually manage all the on-water operations in the area – were also very accommodating to our request to install a mooring (containing longer-term water quality monitoring equipment),” recalled Graham. “The resultant long term water quality data will be very helpful for the success of our research project.”

The data collected from an active dredge program, in addition to the environmental monitoring datasets collected by industry that have been made available to WAMSI, are beginning to contribute to better numerical modelling of the characteristics of sediment plumes from dredging operations. Combined with results coming in from other projects within WAMSI’s Dredging Science Node, greater certainty will be possible in future when predicting the real impacts of marine dredging projects, and how best to minimise them.

Chevron Australia’s Marine HES Advisor, Daniel Kelleher, said that Chevron and its subcontractors worked well with WAMSI researchers to achieve successful outcomes amidst a challenging marine environment.

“The team of scientists from WAMSI safely completed complex plume monitoring tasks within the Wheatstone Project marine construction work area on numerous occasions. Simultaneous operations were well-planned and communicated across WAMSI, Chevron, our prime contractor and marine dredging subcontractor to ensure that all parties could achieve their objectives in the complex marine work environment,” said Daniel.

“Communications between Chevron and the WAMSI team were excellent throughout the planning and execution of the works, ensuring marine safety and environmental protection values were maintained at all times. Information collected through WAMSI and Chevron working together will allow for improvements in best practice environmental management for future dredging programs,” said Daniel.