Vasse MLA Libby Mettam has called for a single agency to manage the water quality in the Vasse River and Geographe waterways..
Ms Mettam said consolidating the management also common sense.
"For too long, we have had multiple agencies trying to manage different parts of the Vasse River and the surrounding Geographe waterways and drainage systems and it simply isn't working," she said.
"The health of the river is suffering as all the different agencies attempt to manage sections in different ways, the various committees established to deal with it have not come up with a cohesive plan and it's having wide-ranging implications beyond the river.
"Action on the river is now urgent and overdue."
In 2013, fish deaths sparked an independent review conducted by professor Barry Hart who released a report titled the Current and Future Management of Water Assets in the Geographe Catchment.
In response to the review, the Vasse Taskforce was established in 2014 with stakeholders from GeoCatch, Department of Water, Busselton Water, Water Corporation and the City of Busselton.
The taskforce set out to improve the management of the Geographe catchment including its governance, funding, drainage, infill sewerage and research.
Ms Mettam said unfortunately, seven years on, many of the issues identified in the report still haven't been resolved and the solutions posed have not been implemented.
"It's very clear that the management and the responsibility for Vasse River and the surrounding drainage and waterways needs to be consolidated and undertaken by one agency to ensure there's a uniform approach and ultimate accountability," she said.
"The Liberals WA will ensure that consolidation and transfer of responsibility is given to one agency as a priority, if elected, to ensure we aren't going round in circles trying to fix these issues in another seven years' time."
City of Busselton director of planning and development services Paul Needham said at times in the past the city had advocated that there be a single 'infrastructure manager', but it has always been understood that there can never, truly, be 'one agency' responsible for everything.
"What has occurred over recent years, though, is that the scale and scope of coordination between the key agencies has increased very significantly," he said.
"The City also agreed to take on the role of 'interim asset manager' for the Lower Vasse River in 2014.
"Prior to that time, there was no agency responsible for management of the river itself.
"In that role, though, the city will continue to rely on the support of other agencies, most notably the Department of Water and Environmental Regulation."
A WA Labor spokesperson said they had no plans to make changes to the management of the Vasse River at this point in time.
"The Hart Review was commissioned by the previous Liberal-National Government and reported in March 2014," the spokesperson said.
"Ms Mettam was a member of the previous government that failed to act on its recommendations."
Greens candidate Mia Krasenstein said the river would benefit from The Greens' annual $125 million Nature Fund, which would establish ongoing funding for critical conservation and rehabilitation projects across WA.
"This fund provides significant scope to work with local Natural Resource Management groups to address the appalling water quality of the Vasse River, which will only worsen as our climate changes," she said.
Have your say: Is enough being done to manage water quality in the Vasse River? What would you like to see happen in the management of the waterways? Email email@example.com.
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