Supporters of the controversial proposal to increase Sydney’s Warragamba Dam wall by 14 metres are using an unlikely event to argue for the proposal, the long-running drought!
Recent surges in dam levels for Sydney’s major water supply could have caused flooding downstream in the Hawkesbury-Nepean region if the dam had been closer to capacity; Minister for Western Sydney Stuart Ayres argued.
As it was, the dam’s storage capacity surged from an anaemic 43 per cent to more than 71 per cent on Wednesday from the three-day deluge that has caused flooding and storm damage on the East Coast.
The Member for Penrith said that the region covered partly by his electorate had only been spared because the dam’s levels had been so low. Warragamba was constructed between 1948–1960 at a time when Sydney’s population was only 2.1 million; less than half what it is now.
“This week has only seen minor to moderate flooding in low areas with some bridges forced to close. This is because the largest tributaries pushed water into the Warragamba Dam that was only around 40 per cent full,” Mr Ayres said.
A State Parliamentary Inquiry is examining the proposal to raise the dam wall announced in 2016 as a means of reducing the likelihood of catastrophic flooding in outer-western Sydney, whose population is forecast to double in the next 30 years.
Environmental groups opposing the plan arguing that unique bushland areas upstream of the catchment would be flooded.
Such objections have seen dam building for urban areas effectively ceasing in Australian due to the heightened concerns for wildlife areas and endangered species in proposed catchment zones.
But Mr Ayres says the topography around the Warragamba catchment means that water can rise quickly and dangerously in parts of the flood plain.