The Barmah sand slug, a complex environmental issue, poses a significant challenge for Australia's Murray-Darling Basin Authority (MDBA). This problem, primarily caused by historic mining practices, has led to a massive accumulation of sand, exacerbating a bottleneck and restricting irrigation flows. The MDBA is grappling with a delicate balance between competing demands, including environmental preservation, community needs, and economic interests.
The sand slug, discovered in 2019, has caused a bottleneck at the Barmah narrows, with the amount of sand clogging the river equivalent to filling the Melbourne Cricket Ground 13 times. MDBA director Natalie Dando warns that the narrows are acting like an hourglass, where sand moves in faster than it can exit, leading to reduced water flow and increased challenges in meeting downstream demands.
The MDBA is tasked with presenting its advice to federal and state governments, considering regulatory processes, costs, and the management of potential works in a frequently flooded area. The authority aims to find a solution with the least impact, one that stakeholders can support.
However, the process is complicated by the contested nature of water management. Bangerang Aboriginal Corporation, for instance, has been consulting with the MDBA, but treaty manager Casey Atkinson highlights the challenge of aligning various vested interests. The issue affects the entire community, and finding common ground among different stakeholders is crucial.
Jodie Hay, an irrigation dairy and beef farmer, believes that erosion caused by high irrigation demand downstream is a more likely cause of the sand slug. She has transformed her property into wetlands at Cohuna, adapting to changing water use processes over the past 30 years due to unreliable allocations and pricing. The high river flows have led to significant bank erosion, with the loss of six to ten meters of riverbank since the Murray-Darling Basin plan's implementation in 2012.
Fluvial geomorphologist Ian Rutherford, engaged by the MDBA, agrees that irrigation flows have caused high erosion but estimates that only 10% of the sand volume could be attributed to this source. He emphasizes that the sand slug is a legacy effect of past land uses and that there isn't a simple solution. Rutherford suggests that moving water around the obstacle is a clear irrigation solution, but he also acknowledges the challenges posed by the MDBA's long and hard river management practices.
In conclusion, the Barmah sand slug issue highlights the complexity of managing a river under high stress, balancing environmental preservation, community needs, and economic interests. The MDBA's task is to find a solution that minimizes environmental impact while addressing the concerns of various stakeholders. This requires a nuanced approach, considering the historical context and the interconnectedness of the river's health and the well-being of the surrounding communities.
