The Barmah Choke is a naturally occurring hydrological feature integral to the functionality, health and long-term survival of forests and wetlands in the central Murray region.
Drought, climate change, river regulation, increased irrigation developments, de-snagging and introduced flow constraints are all contributing to a decline in the ecological and hydrological function of the Murray River and Barmah and Millewa Ramsar sites, and deterioration of the perched riverbanks.
Efforts to overcome the limitations of the Barmah Choke also come with potential impacts.
In recent years, a range of options has been proposed to address the issue of the Barmah Choke. These include building a channel or pipe to bypass the choke, directing flows through irrigation infrastructure and/or anabranches to bypass the choke, allowing water to overbank and flow through the forest to reach downstream users and dredging the river to increase channel capacity.
Each of these options comes with risks to the ongoing survival of our iconic river red gum forests, Ramsar-listed wetlands and unique biodiversity.
Interrupting natural flow patterns, reducing water availability and changing the geomorphology of waterways can have devastating consequences for native wildlife, vegetation and hydrological function.
In an already stressed system, further change could result in:
- unseasonal inundation leading to stressed river red gum forests
- changes to habitat structure limiting breeding and feeding habitat for aquatic animals
- reduction in the availability of water, reducing overall area of inundation and health of habitat for all species
- reduction in flow variability impacting native fish
- increase in riverbank erosion resulting in 'breakouts' and loss of vegetation
- inadvertently redirecting the course of the river
Sensitive and responsive river management is the best available tool to ensure 'The Narrows' and the Barmah-Millewa Forest flow through can be retained in good health, while also servicing the needs of downstream water users.