Warragamba Dam set to spill this evening – current level 99.6% full – minor flood event expected

WaterNSW planning for a spill event from Warragamba Dam storage, beginning tonight

‘Minor flooding possible in Hawkesbury-Nepean from this afternoon’ – BOM

Inflows to the dam storage – which is near capacity after months of inflows – are rising as a result of the current rain event, which could total up to 75-100mm, says WaterNSW this morning.

“WaterNSW modelling indicates that on Saturday morning the peak spill volume may reach a rate of up to 100 gigalitres per day (GL/day),” said a WaterNSW spokesperson.

That flow figure – a gigalitre is a billion litres – is well below the March spill levels, when we had the major flood. Back then 500GL/day was spilling.

“Downstream impacts are likely,” says the spokesperson, “and will be determined by the spill volume combined with downstream tributary flows.”

WaterNSW is working closely with the Bureau of Meteorology (BOM) and the NSW State Emergency Service to monitor weather and inflows, says the spokesperson.

BOM warned last night of ‘minor flooding’ in the Hawkesbury Nepean Valley – that’s likely to happen by tomorrow.

Here’s BOM’s latest warning in just now – 11.10am:

MINOR FLOODING POSSIBLE IN THE HAWKESBURY-NEPEAN VALLEY FROM FRIDAY AFTERNOON

A trough of low pressure lies over inland NSW bringing rain and thunderstorms across the state into the weekend. This rainfall may cause new and renewed flooding across NSW inland rivers and the Hunter River, many of which have been impacted by recent flooding. Rainfall is forecast to extend across the Hawkesbury-Nepean Valley, where flooding may develop from Friday into the weekend.

For up-to-date Hawkesbury river height levels, check out our friends at Hawkesbury Flood Statistics Unit here for reliable information on that.

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