SENSITIVE marine monitoring instruments retrieved from Cleveland Bay have revealed the ferocity of Severe Tropical Cyclone Yasi.

The wave and current measuring instruments were deployed last October as part of an exhaustive environmental impact assessment process being undertaken to guide future port development.

Study leader Greg Fisk from environmental consultancy group BMT WBM said the instruments had, however, also provided a rare opportunity to record some of the highest waves ever experienced in Cleveland Bay as Cyclone Yasi crossed the Queensland coast.

“Based on the data collected, waves in Cleveland Bay during the cyclone were consistently over five metres for a number of hours,” Mr Fisk said.

“Individual peak waves would have been significantly higher than that, possibly up to 10 metres.

“Extreme waves such as those experienced during Cyclone Yasi have the potential to cause significant damage to coastal structures if they are not of an appropriate design standard.

“The large waves also cause substantial mobilisation of the seabed sediments which can have a significant influence on coastal erosion and disturbance or destruction of marine ecological communities such as seagrasses and corals.”

The instruments were housed in frames to prevent them becoming buried in sediment and placed at a depth of 15 metres which ensured they remained in position during high seas.

One device was deployed offshore from Arthur Bay immediately to the east of Magnetic Island while the second was situated off Cape Cleveland close to the port’s approved dredged material placement area.

Mr Fisk said oceanographic data logged by the monitors during the cyclone would now be compared against meteorological data such as wind speed and direction to provide a greater understanding of how Cleveland Bay functions and reacts during extreme weather events.

The real-time wave and current data collected in the months prior to Cyclone Yasi will meanwhile help calibrate computer models of Cleveland Bay to simulate existing oceanographic processes such as waves, tides, currents and associated sediment transport.

The ferocity of the ocean at the Port of Townsville as Cyclone Yasi approached.