The Swan River Trust has completed full scale field trials of boat wash and wind waves on the Swan River to verify results in its groundbreaking 2009 report, Investigation into the Effect of Wash of Boats and Wind Waves on the Swan River.

The field trials confirmed that a reduction in boat speed limits in sections of the Swan River would dramatically reduce the potential for shoreline erosion, damage to wildlife habitats and disruption to other aquatic users.

Trust Riverpark Manager Chris Mather said the results would be used to help inform a major review of aquatic usage on the Swan and Canning rivers in a collaborative arrangement between the Trust and Department of Transport.

“Involving extensive stakeholder and community consultations, the review will begin later this year and include a review of speed limits on the river along with other management strategies,“ Mr Mather said.

Boat wash and wind waves were measured at different locations on the Swan River including Ashfield Parade and Quarry Point. Nine different hull forms were tested across a range of boat speeds and distances from the shoreline.

The results from trials at Ashfield Parade showed that the speed of 8 knots (the present speed limit) roughly corresponds to the highest-energy boat wake for most recreational vessels.

Only at speeds less than 6 knots did all the vessels produce less wave energy than the extreme wind waves at Ashfield parade. At 5 knots, all vessels produced minimal wash.

Wind wave measurements were also carried out at these locations in order to validate the empirical method used for wind wave predictions.

Captain Cook Cruises and Rottnest Express provided ferries and Boating Industry of Western Australia (BIAWA) organised a range of aluminium and fibreglass recreational vessels belonging to their members. The Trust vessel Noel Robins was also tested.

Riverpark Manager Chris Mather said the support of ferry operators and BIAWA was a big boost to the research.

“There is little local research available on boat wash and wind waves so we are pleased to be adding to the knowledge available,” Mr Mather said.

“The research is part of a bigger strategy to understand the effects of boating on the Swan and Canning rivers,” he said.

The second stage research was undertaken by Curtin University’s Centre for Marine Science and Technology for the Swan River Trust. The Trust worked in collaboration with the Department of Transport.

The report is available on the Swan River Trust’s website.

Media contact: Bridget Tombleson 9278 0953 or 0434 603 684