The report, which looked into the health of the Swan Canning River System, found that despite 20 years of monitoring and intervention, the health of the system was still worsening.
Key findings of the report released by the Office of the Auditor General include moderate to poor water quality, unsuccessful action to combat sources of nutrients and pollutants, gaps in planning and reporting, and the lack of an approved River Protection Strategy.
Auditor General Colin Murphy said symptoms of poor water quality included low oxygen levels, high nutrient levels and fish deaths that exceeded the Swan River Trust’s (SRT) target in four of the past 10 years.
The report lists key recommendations for the SRT to work closer with Parliament, take action to have its River Protection Strategy approved and clarify responsibility for the river.
Environment Minister Albert Jacob said he acknowledged more work needed to be done to ensure good river management, but improvements were evident.
‘Nutrient intervention technologies continue to be a major focus with the construction of end-of-catchment wetlands in Ellen Brook and Bayswater catchments, together with the construction of a new oxygenation plant on the Canning River,’ he said.
Mr Jacob said a 2013 Fish Community Report by Murdoch University found the health of the river was improving, with the ecological condition of the rivers getting better since the mid 2000s.
He said a River Protection Strategy would be finalised after the merger and transfer of day-to-day management functions of the Swan River Trust to the Department of Parks and Wildlife.
Greens MLC Lynn MacLaren said it was clear that more research was necessary to effectively implement best practice.
‘We must act now before the fragile eco-system of the river system becomes completely irreparable,’ she said.