Residents of the Hawkesbury-Nepean Valley are already being warned to prepare for flooding with Sydney’s largest dam set to reach capacity.

The NSW government is seeking to raise the Warragamba Dam wall by 14 metres, but has received ongoing backlash from environmental and Indigenous activist groups.

Minister for Western Sydney Stuart Ayres told Ray Hadley the measure will prevent floods or allow greater time to evacuate residents.

“Right now there is no flood mitigation capability at Warragamba Dam.

“The water … must be released downstream into the low-lying areas around Penrith and Hawkesbury.”

Mr Ayres acknowledged there would “no doubt” be an environmental impact, but stressed inundation of 0.04 per cent of the World Heritage-listed area would only be temporary.

“It would only be whilst we’re holding that water behind the dam wall so it wasn’t in people’s living rooms, or flowing through streets and towns.

“We’re not giving up any more time; we’re not bowing to what is, for all intents and purposes, environmental terrorism.”

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