Federal Labor have announced $3 million for the Peel Harvey Catchment Council if their Canning candidate Mellisa Teede is elected.
On Friday, Ms Teede joined Mandurah MP David Templeman, Brand MP Madeleine King, Peel Harvey Catchment Council (PHCC) chairman Caroline Knight and chief executive Jane O'Malley to announce the potential cash splash to clean up local waterways.
The funding will be a project under the Urban Rivers and Corridors Program and will be used for priority works converting drains into wetlands to capture and filter stormwater.
Member for Brand Madeleine King said the promise was an example of a "future Shorten government's commitment to the environment".
"In a beautiful place like Mandurah and across this whole Peel inlet, that's so important for the local community - for the people that fish here, the people that simply enjoy the estuary from day-to-day and tourists as well," she said.
Ms Teede echoed her colleague's sentiments, adding that the funding would be used towards a number of important initiatives.
"I'm excited because what I know of the Catchment Council is they are absolute leaders in this community and I'm so impressed with the range of projects they've been doing," Ms Teede said.
PHCC chairman and Mandurah deputy mayor Caroline Knight welcomed the support.
"We're very happy, delighted in fact, with this announcement," she said.
"Our waterways are the economic basis of the Bindjareb region and science has shown us that our waterways are in poor condition so this will go a long way to assist in helping to improve that.
"This will help restore the health of internationally significant RAMSAR wetlands."
As part of the promise, if re-elected, Labor will engage state and local governments, local councils, community groups and local environmental organisations to bring the urban waterways back to health.
The commitment to cleaning up urban rivers is part of a broader strategy to restore Australian oceans to health, including marine parks, as well as tackling waste and plastics.