Hawkesbury Community Alliance calls on NSW government to act now on urgent flood mitigation

Hawkesbury Community Alliance – a new and rapidly growing local community group – is calling on the NSW government to investigate flood mitigation options ahead of the predicted third La Nina and the Indian Ocean Dipole events which could coincide in Spring, potentially leading to yet more floods for our region.

Windsor Bridge completely under flood waters back in March this year, and it would happen again in July…

The group do not believe the proposed decade-long build of a raised dam wall at Warragamaba is what the flood-ravaged Hawkesbury community needs, rather they have launched a call for action right now, chiefly to let water out of Warragamba Dam – currently sitting at 100% full – a level we have constantly seen for around a month, which means the Dam is constantly spilling.

If there is a major rain event in the next month or so we could see yet another major flood event, which would make it six Hawkesbury floods in two and a half years.

“The NSW government stubbornly remains focussed on raising the dam wall, which is a project that will take several years,” HCA spokesperson, Samantha Magnusson says.

“Our community needs flood mitigation now, not in the distant future.”

“At the recent Upper House Select Committee public hearing held in Windsor

on June 3, there was unanimous community support for the government to change the legislation and allow Warragamba Dam to be used for flood mitigation,” Ms Magnusson said.

The HCA are calling on the government to allow the Full Supply Level (FSL) of Warragamba Dam to be lowered ahead of predicted flooding to prevent a repeat of the devastating July 2022 scenario.

In that last flood, says HCA, water began spilling over the dam wall at 2am, without any warning to the community through the Water NSW Early Warning Network.

Let water out of Warragamba Dam before expected flood events, says HCA…

Ms Magnusson says as a result, the community was caught off-guard.

“An unprecedented increase in water level and flow velocity resulted in a much-

reduced evacuation timeline, excessive flood damage, and irreparable damage to the riverbank, all of which could have been prevented if managed differently,” Ms Magnusson said.

HCA is also critical of Hawkesbury Council, with Ms Magnusson saying they are, “reluctant to consider lowering dam levels beyond five metres, while the NSW Government has all but ruled out using the dam for flood mitigation”.

There is overwhelming scientific evidence that a reduction of up to 12 metres is possible, says HCA, “and with sufficient planning and accurate long-range weather forecasting, Sydney’s drinking water levels can be sustainably managed”, says Ms Magnusson.

To start a conversation with the public and local, state and federal governments on the opportunities for using the Warragamba Dam for flood mitigation, HCA will be hosting a public information session with University of NSW’s Dr Stuart Khan. The meeting is not intended to debate the merits or impediments to raising the dam wall, says HCA, which they point out is several years out.

Dr Khan is what you’d call an expert – a Professor in the School of Civil & Environmental Engineering, and Director of the Australian Graduate School of Engineering (AGSE).

Dr Stuart Khan will be in the Hawkesbury at a public meeting on August 20…

He is also a member of the Independent Metropolitan Water Advisory Panel, advising the NSW Government on the Greater Sydney Water Strategy.

He is widely considered one of the leading experts in water management and

will discuss all the aspects of lowering the Full Supply Level (FSL) of Warragamba Dam at a meeting in the Hawkesbury on August 20.

Dr Khan says,

“Many cities reserve some of the available water storage capacity in their dams for flood mitigation and this is an opportunity that should be more seriously considered for Warragamba Dam.”

“Reserving some capacity for flood mitigation will have implications for Sydney’s drinking water supply security, but there are already strong arguments for reducing our reliance on Warragamba Dam and replacing that supply security with rainfall independent water sources, such as seawater desalination and purified recycled water,” says Dr Khan.

“It is essential to consider the ‘big picture’ for water management in Sydney, rather than look at individual components in isolation,” says points out.

Hawkesbury Community Alliance is inviting all those interested to a public information forum about flood mitigation, featuring Dr Khan, on Saturday August 20 at the Hawkesbury Race Club, 1 Racecourse Rd, Clarendon NSW 2756 from 4-5pm.

The event is ticketed but free. You must have a ticket for entry and tickets can be obtained here https://www.trybooking.com/943758 or via Hawkesbury Community Alliance Facebook page.

The HCA is an umbrella group of several existing community groups from the Hawkesbury region.

The group says its goal is to create community awareness of different regional issues – from disaster resilience to infrastructure, small business issues, telecommunication problems, and the interests of special needs groups.

The foundation members include Sick of North Richmond Traffic Snarls, Hawkesbury Resident and Ratepayers Action (HRRA), Hawkesbury BLOR Action Group (BLORCAG), Hawkesbury Matters, North Richmond Districts Community Action Association (NRDCAA) and Hawkesbury Nepean Flood Mitigation Action Committee.

The group says it is also in discussion with 15 other Hawkesbury community groups.

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