Restoring the Murray River's estuary

For years now I’ve been writing about the barrages that block inflows from the Southern Ocean making the vast shallow coastal lagoons at the end of the Murray River completely dependent on Murray River inflows. Without the barrages the sea would push in each autumn and for longer periods during drought.

During the recent drought water levels in Lake Alexandrina fell precipitously from 0.85 metres above sea level to -1.10 metres below. There was simply not enough water in upstream storages to keep both Lake Alexandrina and the adjacent Lake Albert supplied with adequate freshwater, notwithstanding the Snowy diversions and strictly limited allocations for irrigation during the drought.

The South Australian government could have opened the 593 gates within the barrage structure to let the Southern Ocean in, but instead kept the gates shut tight. This was not reported in the national media, instead, during the drought, television cameras focused on either the receding lake waters or the sand dredge working to keep the Murray’s mouth open, conveniently avoiding images of the barrages in between.

As soon as the floodwaters arrived in the spring of 2010, the South Australian government opened the gates to let excess water out.

It’s a no brainer, if $10 billion is to be spent saving the Murray Darling as part of a grand plan for water reform, something must be done about the barrages and restoring the Murray River’s estuary. But there is not one state or federal politician who will take up this issue or publically acknowledge that the current management of Lake Alexandrina as an artificial freshwater oasis is unsustainable.

That was my message to Labor, Liberal, National and Greens Senators and MPs representing voters from across the Murray Darling when I visited Canberra in July last year. My trip was funded by Johnny Kahlbetzer from Twynam Agricultural Group. My message was that: The health of a river system is more than the quantity of water flowing downstream;
the current management of Lake Alexandrina as an artificial freshwater oasis is unsustainable; and
restoring the Murray River’s estuary must be a priority in any Murray Darling Basin Plan.

I was surprised to learn that all the politicians seemed to know about the barrages: the 7.6 kilometre wide wall that holds back the tide.

And they mostly agreed when I suggested that much of the current water reform agenda is based on a false premise because the water being ‘saved’ is likely to end up in Lake Alexandrina that is not a natural environment.  

But the same politicians said restoring the estuary would be too hard, too political, and it was potentially a vote loser in South Australia. 

It is South Australian government policy that Lake Alexandrina be considered a freshwater lake. This story goes right back to the foundation myths associated with the settlement of that state. In the 1800s potential migrants were encouraged to buy land, sight unseen, on the basis that Lake Alexandrina was a fresh water lake and had a reliably navigable passage to the sea. Both untrue.

Most South Australians have never come to terms with the true nature of the Lower Murray and building the barrages across the five channels that converge on the Murray’s Mouth has just made things worst. So they mostly avoid any discussion of the barrages and instead conveniently, but wrongly, shift the blame to upstream irrigation.

If the proposed Murray Darling basin water plan goes ahead it will be just building on this nonsense and the real issue, the barrages, will not be addressed. Indeed the federal government is intent on spending $10 billion to significantly reduce food production in the Murray Darling, but for no environmental gain while ignoring the potential benefits of restoring the Murray River’s estuary.