Farmers in the southern Tablelands are facing flooding from a plan to raise the Wyangala Dam wall in central west New South Wales.

Kerri and John Webster run a mixed farm operation on the Lachlan River just upstream of the dam, saying their intergenerational farming business is threatened by the proposal.

Flood maps show that the low-lying river plains on Webster’s farm will go underwater when the proposed new dam is full.

“This country is our powerhouse. It’s here, your best lambs, your best beef, your best alfalfa come from and [if you] take it out, it’s going to ruin our business, “Webster said.

Websters said the NSW government was trying to flood an agricultural region to supply water further downstream.

“They’re stealing Peter to pay Paul, and we’ll be sacrificed in the process,” Mrs Webster said.

Upper Lachlan branch of NSW Farmers’ Association chairman Robyn Alders said there had been no consultations with farmers upstream of the dam and that there were other more cost-effective ways to improve water safety.

In western Riverina, landowners and environmental groups are concerned that a larger dam could reduce natural flooding to nationally significant wetlands, such as the Great Cumbung Swamp, where the river ends.

From boom to bust

Irrigator and Lachlan Valley Water Chair Tom Green said farmers in the district were already feeling the effects of climate change.

“[The Lachlan Valley] has previously been known as a safe alfalfa-growing area … [with] a lot of hay production and sheep production. “

Mr Green said the region had been in a precarious situation with water during the last two major droughts and a larger dam would help save more water during wet periods.

He said a major dam would be a “game changer” for the region in terms of alternatives such as efficiency upgrades to the irrigation scheme.

“[The projects] will not provide, I do not think, the level of change, a step-change in water security for everyone in the valley, “he said.

Dam (n) expensive

The project would add an additional 650 gigaliters to the total storage capacity, an increase of more than 50 percent.

Water NSW estimated that the larger storage would on average provide 21 gigalitres extra per year for ordinary water users.

A recent parliamentary inquiry into the New South Wales Upper House found that the cost of the project could now be as high as $ 2 billion.

State Water Secretary Melinda Pavey said the final business case was still months away and that changes to the biodiversity compensation scheme were a “significant” cause of the cost blow.

“So that’s the main reason there have been changes in the law since the initial price estimates were made,” she said.

The Biodiversity Compensation Scheme was also responsible for significant cost increases with the plan to raise the Warragamba Dam Wall, Sydney’s main drinking water supply.

Mrs Pavey said the government was still fully committed to Wyangala project despite the increased costs and delays.

Are dams worth the money anymore?

Water infrastructure expert Professor Stuart Khan, from the University of New South Wales, said that while the increase in the dam stores more water for local farmers, water will be at the expense of elsewhere.

“What we need to remember about the Murray-Darling Basin is that it is a fully allocated system-there is no extra water,” he said.

“If we want to make more water available to a person, we take that water from other uses, whether it’s environmental or it’s an allocation somewhere.”

Professor Khan also said a larger dam could reduce currents to the wetlands at the bottom of the river that were important for restoring groundwater reserves.

“So these groundwater systems are missing water and you have big swamps and you have big wetlands that are very environmentally important wetlands.”

Professor Khan said it was important to wait for the final business case, but as the cost of building dams increased, water recycling, managed groundwater charging and efficiency programs could be more viable alternatives to improving water safety.

“The further we go down the track after building more and more of the second-best dams, the more of these alternatives will become more and more favorable in comparison,” he said.