Flemington Racecourse's controversial levee worsened widespread flooding of Melbourne homes but won't be ripped down.
About 600 properties in Melbourne's inner west were flooded when the Maribyrnong River broke its banks on October 14, 2022.
But the Melbourne Cup track remained clear because of its 2.5m high and 900m long wall built in 2007.
Former Federal Court judge Tony Pagone investigated the impact of the wall as part of an independent review established by Melbourne Water into the Maribyrnong floods.
His final report, released on Friday, found the wall contributed to the extent of flooding across the catchment by about one per cent.
Flooding depth was increased between 8 to 10mm in the upstream areas and up to 30mm in downstream parts of the Maribyrnong township, impacting about 240 residential properties.
Some houses may have avoided flooding altogether if not for the levee.
"(The flood wall) most likely resulted in flooding of some houses that would otherwise not have flooded and increased the flood damage in houses that would have been flooded in the absence of the flood wall," the report stated.
Modelling showed flooding of the industrial areas of West Melbourne and Kensington next to the river was 60 to 65mm higher because of the wall.
Compensatory works reduced the flood level between 8mm to 10mm about 500m upstream of Footscray bridge and between 4mm to 8mm for a further 2km upstream.
"Beyond this, the impacts of the compensatory works were negligible," the report said.
Despite the wall's impact on homes, Melbourne Water said it did not believe there was enough evidence to justify removing it.
"The independent review panel does find the mitigation works put in place to offset the impact of the wall didn't perform as well as expected," managing director Nerina Di Lorenzo said.
"We will now incorporate an examination of the flood wall mitigation into our broader investigation of potential mitigation options across the catchment."
The Victoria Racing Club, manager of the renowned racecourse, noted the flood wall was approved by the Bracks government in 2004 and complied with all relevant requirements.
The club had received the final report on Friday morning and will consider its findings, including those relevant to the racecourse.
"We remain committed to working with the appropriate authorities on this matter," VRC said in a statement.
The review also concluded the levee had no measurable impact on the Rivervue Retirement Village in Avondale Heights, where 70 residents were forced out of their homes following the inundation of 47 properties.
A state parliamentary inquiry into the 2022 statewide floods heard Melbourne Water's modelling completely underestimated the risk to Rivervue.
The agency said it would continue to implement 15 recommendations made by Justice Pagone in 2023.
A Victorian government spokeswoman said it would work with Melbourne Water to address the report's findings and identify areas to improve flood mitigation, communication and response efforts.
