The river’s regulated flow capacity through the reach — often known as the Barmah Choke — is reducing due to the build-up of sand on the river’s bed from upstream gold mining and land clearing practices in the 1800s, according to the Murray-Darling Basin Authority
The MDBA said research showed the amount of water that could flow through this section of the river has decreased during the past three decades from 11,300 Ml/day to 9200 Ml/day.
This means about 20 per cent less water can flow through the reach in summer, which has environmental, cultural, social and economic ramifications.
Basin governments in February committed $2.35 million to the next stage of the Barmah-Millewa program.
MDBA’s Andrew Reynolds said the options on the table had been refined, with the current focus on smaller projects that could be implemented more readily and cost effectively.
The options to be further investigated include:
- Sediment management work within the Barmah-Millewa reach.
- Increased use of the Murray Irrigation Limited infrastructure by using existing and upgraded outlets.
- Use of the Victorian mid-Murray storages (excluding Ghow Swamp) to mitigate risk of delivery shortfall.
- Optimising the timing of transfers of water from Hume Dam to Tar-Ru (Lake Victoria) with consideration of environmental opportunities and reducing unseasonal flow.
- Use of the Murrumbidgee weirs to mitigate the risk of delivery shortfalls.
“Of the five options now being considered, no decisions have been made about which would be implemented — all the options are technically feasible but further scrutiny will be an important next step,” Mr Reynolds said.
“This reach is significant to First Nations people, it supports Ramsar-listed wetlands and has a thriving tourism industry that sustains local communities — it has high cultural, environmental, social and economic values.”
Mr Reynolds said the MDBA would continue to engage with First Nations and communities throughout the program.
“In the coming months we’ll also be undertaking further modelling and riverbed measurement to understand if the recent floods have further reduced the capacity in this section of the river,” he said.
For more information, visit: https://www.mdba.gov.au/publications/mdba-reports/barmah-millewa-program
