Delegates at the River reflections annual water conference today heard about the impacts of the massive sand slug in the Barmah-Millewa reach of the Murray River and the consequences to water users, the environment and local community if no action is taken to address it.
The Barmah-Millewa reach is the narrowest section of the river that runs through the Barmah-Millewa Forest near Echuca and Deniliquin in the mid-Murray region. Capacity through the Barmah-Millewa reach has reduced from 11,300 ML/day in the 1980s to 9,200 GL per day today.
Independent experts in fluvial geomorphology, stream management and river research have been gradually surveying the riverbed over the past 18 months and estimate 20 million cubic metres of sand is on the riverbed between Yarrawonga and Picnic Point.
Murray-Darling Basin Authority (MDBA) Director of River Murray Operations Tyson Milne told delegates it's understood the sand was largely caused by land-use practices and mining in the rivers upstream centuries ago.
"We are talking about 13 Melbourne Cricket Grounds full of sand which is quite phenomenal," Mr Milne said.
"There is no silver bullet to this complex problem and the ecological, cultural, economic and community implications of any course of action are being considered.
"We cannot afford to do nothing because the problem is getting worse."
Studies show the sand is continuing to move downstream, and into the RAMSAR-listed national parks, increasing erosion and impacting cultural sites and access to recreational areas. The build-up of sand is also increasing the risk of the Murray River changing its course.
"Within 10 years, the build-up of sand in the Barmah-Millewa reach will have a major impact on our ability to deliver water downstream," Mr Milne said.
"Over the past 12 months we have been talking with the community, First Nations groups, irrigators, government and councils to get their perspectives and input on how this problem could be addressed."
Drawing on the input from the community, and extensive investigation and independent research, the MDBA has been asked by Basin state governments to develop options for governments to consider.
The six options being explored are:
- a 5-year project to stabilise banks and reduce degradation to prevent further losses into the Barmah Millewa Forest
- selectively removing the sand from key locations where riverbank erosion is accelerating, causing environmental, cultural loss
- making changes to timings of water transfers to Lake Victoria - Tar-Ru
- using Goulburn Murray Irrigation District's existing and new infrastructure to relieve pressure on the Barmah-Millewa Reach
- using Murray Irrigation Limited system to deliver water to natural ephemeral creeks of the Edward/Kolety - Wakool - Niemur river system
- assessing the potential to transfer Snowy Releases to the Murrumbidgee for delivery to the Murray River
A preliminary scoping report will be published by 30 July 2022, with a business case due in late September, and final report in December 2022.
The options will be considered by water ministers at their next Ministerial Council meeting.
The project plan is available at the MDBA's website: Barmah-Millewa Feasibility Study | Murray-Darling Basin Authority (mdba.gov.au)
The River reflections annual water conference is taking place in Mildura, Victoria on Wednesday, 1 June and Thursday, 2 June 2022.
River reflections provides the space and time for the diverse communities and industries of the Murray-Darling Basin to come together. It is an opportunity to share innovations in water management, knowledge and lessons learned while celebrating achievements.
