Central West dams capture large inflows, reducing floods

Central West dams capture large inflows, reducing floods

07 July 2022

Central West dams have captured large volumes of inflow in recent days, holding back water to minimise downstream flooding in the Macquarie and Lachlan valleys.

Burrendong (132%) and Wyangala (102%) dams have both risen into flood surcharge zones after receiving 430 gigalitres (GL) and 150 GL respectively, from an unexpectedly intense rain event which crossed the state over the weekend.

Both dams functioned to greatly reduce downstream flood impacts by holding the water back to allow significant downstream tributary flows to peak and begin receding, before releases from the dams were increased.

WaterNSW has set up a dedicated incident team to manage the situation and is working closely with the Bureau and the NSW State Emergency Service to monitor weather and inflows.

Burrendong Dam (Macquarie River).

Burrendong Dam is at 132% of capacity and releasing 17 gigalitres per day (GL/day).

The storage has risen from 107% at the start of the inflow event, up to 132% without the need for major releases during the peak inflow period.

The valley’s flood reference panel met yesterday (7 July) and agreed on a release strategy to maintain a flow at Gin Gin of approximately 28 GL/day to draw storage down to 120%.

Any rain sufficient to generate inflows will delay the draw down. If this situation arises, the release strategy will be revised.

Wyangala Dam (Lachlan River)

Wyangala Dam is 101.6% full and 21 GL above full supply level, with inflows falling to 8.7 GL and releases currently 14 GL/day.

The rainfall event has so far generated 150 GL of inflow to Wyangala dam with a peak instantaneous inflow of 122 GL/day on 3 July.

Releases are likely to remain around 10-14 GL/day over the coming days to pass inflow and gradually draw the storage below the current surcharged level.

For more information:

Agency

Information

Website

Bureau of Meteorology (BOM)

Weather forecasts and warnings

BOM

NSW State Emergency Service (SES)

Flooding and severe weather warnings and advice

NSW SES

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98.7
Friday 12 August
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2,585,768 ML
2,618,706 ML
7,913 ML
1,131 ML
-7,334 ML
Friday 12 August