Protecting the Lachlan Valley from major flooding during the weather events the area is currently encountering should be a high priority of the NSW government when considering the raising of the Wyangala Dam wall, according to Lachlan Valley Water.
It will reduce the chance of major flooding in the Lachlan Valley and improve water security for irrigators and towns Condobolin, Lake Cargelligo, like Forbes, Parkes, Cowra and Hillston, they say.
Wyangala Dam reached 95 percent on 28 July and the current airspace release of water shows the urgent need for an increased capacity of the dam, Lachlan Valley Water expressed.
“Excellent winter rainfall has seen the dam close to filling for the first time since 2016 and with significant tributary flows as well, has now increased the risk of flooding downstream along the Lachlan River in coming weeks,” a Lachlan Valley water statement said on 28 July.
“WaterNSW is managing this very actively with airspace releases, and like everyone, I’m hoping we won’t see the devastating floods of 2016 repeated, given the negative Indian Ocean Dipole we are currently encountering,” Lachlan Valley Water chair, Tom Green, explained.
“It’s extremely important under the current climatic variability that the Lachlan Valley can store more water in very wet years, to help manage both flood events and the drought periods we will encounter in the future.
“In 2016 we saw massive damage to crops and road infrastructure, amounting to hundreds of millions of dollars according to the Regional Recovery Co-ordinator, and the Newell Highway was closed for six weeks, with significant flow-on impacts for transport companies, travellers and everyone”, said Mr Green.
“Small floods are good for the river and it is important that significant flows reach the lower Lachlan for floodplain inundation, the Great Cumbung Swamp and all the environmental needs but much of this water can also have a substantial flooding impact upstream, so the aim is to try and manage this.”
The Wyangala Dam Wall Raising project is expected to increase the dam’s capacity to hold an additional 650 gigalitres, which will increase capacity by 53 percent.
The proposed project will see the dam wall height raised, which will increase the Full Supply Level by 10 metres.
“One of the important messages about the Wyangala Dam project is that it’s not about increasing extraction above the Basin Plan sustainable diversion limit, but about providing more security for water availability under a more variable climate,“ Mr Green stated.
“We’re urging the NSW Government to get on with this project to both greatly reduce the chance of major flooding in the Lachlan Valley and improve water security for irrigators and towns like Forbes, Parkes, Cowra, Condobolin, Lake Cargelligo and Hillston.
“We saw the drought that followed 2016, which set in very quickly and lasted over three years. This is likely to occur again in the future and the dam wall needs to be raised before we encounter the next major dry period, to protect our communities, businesses, agriculture and the environment.”