Call for better stormwater filtration at Hobart beaches after suspected poor water quality sees water races cut

All Greater Hobart beaches need grates over stormwater drains to prevent pollution ending up on shorelines and in the River Derwent, a marine protection group says.

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ALL Greater Hobart beaches need grates over stormwater drains to prevent pollution ending up on shorelines and in the River Derwent, a marine protection group says.

A 40mm downpour of rain on Friday night brought with it reports of debris washed up at Eastern Shore beaches this weekend as authorities advised against swimming in the Derwent.

Several water events on Day Three of the Royal Hobart Regatta, including the Trans Derwent Swim and the power boat races were cancelled amid water quality concerns.

The government-partnered Derwent Estuary Program’s Bay Watch website shows poor water quality was this month recorded at Hobart Rivulet [mouth], Sandy Bay’s Marieville Esplanade and at Brown’s River, Kingston.

Tasmanian Alliance for Marine Protection co-vice chair Sheenagh Neill – a regular sailor in state waters – said councils should be doing more to prevent debris passing through stormwater drains.

“One of the things the councils don’t do well here is put in grates over stormwater drains, because when we have big rain events, our beaches end up with anything deposited by people on the street,” she said.

“Stormwater debris is to be expected after a large rain event is to be expected because unfortunately we’re way behind the 8-ball. We call ourselves sustainable but we aren’t.”

Ms Neill said authorities also needed to better assess aquaculture infrastructure after severe weather events to address water pollution.

Clarence City Council general manager Ian Nelson said the council already had a number of pollutant traps installed on mains.

“These traps stop debris entering waterways and we have a program aimed at progressively upgrading our stormwater system,” he said.

Derwent Estuary Program chief executive Ursual Taylor said authorities were working with local councils to identify which catchments needed better filtration systems.

“Lots of sites have them already but you can’t see them as they’re often underground but it’s something we’re hoping to help identify as a priority,” she said.

“We can all make a difference through a simple combined effort like picking up after dogs and washing cars on grass or at car wash facilities. This will be better for our marine life.”

The River Derwent has been plagued with sewage issues in recent years, including an incident in 2019 when around 6 megalitres — more than two Olympic-size swimming pools — of untreated sewage and stormwater run-off was discharged into the river from a Macquarie Point treatment plant.