NSW dams see huge increase in stored water after 2021 floods

Drought-barren dams across NSW have swelled up to 25 times their size in as little as 18-months following heavy rains and flash flooding.

Drought-barren dams across NSW have swelled up to 25 times their size in as little as 18-months following heavy rains and flash flooding.

It comes as more than a week of consistent rainfall broke the banks of rivers across the state, and sparked hazardous flood and fast-flowing waterways.

And farmers in regional areas are now starting to see the benefits.

The state is now almost entirely out of the drought with just 1 per cent of NSW classified as drought affected.

In January last year the entire state was declared as in drought.

The Hume Dam wall in full flow near Albury Wodonga. Picture: Simon Dallinger

NSW Farmers president James Jackson said the drought has taught farmers, producers and regulators important lessons about water infrastructure.

“Most people are upbeat about the moisture levels in the ground. The floods did cause some issues but there’s money in mud,” Mr Jackson said.

“One of the big leanings from the drought is that a lot of the modelling around was that it did not anticipate the depth and breadth of the drought. This modelling has been readjusted and there is now a greater impetus on the investment in water infrastructure.

“Water NSW have largely been very good but the drought and now the most recent floods help show the value of having engineers and people in charge of infrastructure involved when it comes to water management.”

Lake Keepit had water levels under one per cent during the worst of the drought. Picture: Peter Lorimer.

Chaffey Dam near Tamworth at 13 per cent capacity last year. Picture: Toby Zerna

The largest increase in dam storage was at Keepit, near Tamworth, which swelled from being 2.6 per cent full in January 2020 to 63.1 per cent on April 1.

This is a 268,071.3 ML increase – which equates to about half of the amount of water stored in the Sydney Harbour.

Split Rock, north of Tamworth, saw the next largest increase.

Booming from 1.7 per cent to 28.6 per cent in the same time frame.

In the last week of March, more than 400mm was recorded on the Mid North Coast and Northern Rivers area.

The heaviest rainfall hit Mount Seaview which had 815mm during a five-day period.

Moree Plains Shire Council Mayor Katrina Humphries said her community was heavily impacted by the floods but they have managed to see the bright side

“I believe the drought has broken,” she said.

“The amount of rain we have had is now impacting the subsoil moisture. Which is something we have not had for years. If there is not moisture below the top 10-15cm you have to survive on the grass on the top. To grow grain you need a deep profile of moisture.”

An Aerial view of Warragamba Dam overflowing in the Western Sydney region where major floods have hit the area in Sydney, Australia. Picture: NCA NewsWire / Gaye Gerard

NSW Water Minister Melinda Pavey said the government will continue to invest in water infrastructure.

“It has been very pleasing that recent rainfall in parts of NSW has meant some of our regional dams have seen a 20 per cent increase in stored water,” she said

“However, NSW is only a year removed from the end of the last drought and many dams are less than half full.”