During the Millennium Drought I did some photography around the edge of the shallow freshwater Lake Alexandrina, including the the seaside towns of Clayton and Milang. At the time, given the absence of sufficient flows dredging was undertaken to keep the Murray Mouth open and to ensure salt and other pollutants could be flushed out of the river system.
With minimum to no flows in the River Murray during the drought, the lake was drying out, as can be seen in these photos made of the foreshore of the lake at Milang:
It was a sad sight seeing a lake dry up. I understand that it was much worse at Lake Albert as water had to be pumped into the lake to mimimize the extent of the ex[posed acid sulfate soils.
The history of the rivers in the Murray-Darling Basin has been one where the focus has been on maintaining sufficient flows to maintain regulated water levels, water allocations for irrigators, and sufficient quality to meet irrigations and drinking-water requirements.
Between 2007 and 2010 there was zero discharge of the river to the sea and, consequently, there was saline seepage from the barrages into Lake Alexandrina increasing the salinity levels in the lake. The level of the lake fell below sea level.
Lower flows are now much more frequent in the Murray River system because of the large scale extraction for agriculture and river regulation. This has meant declining populations of mulloway fish, pipies etc and the degradation of the coastal marine ecosystems.
This drying out of a lake from lack of water is happening at the Menindee Lakes. The NSW Government is reducing the size of the Menindee Lakes ie., letting Lake Cawndilla run dry more often– as the main way the state can “bridge the gap” between the 1,312GL of water it has pledged to deliver back to the environment under the Murray-Darling Basin plan and the 345GL still outstanding. So the pressure is off the NSW irrigators who will not be required to surrender water as NSW tries to meet its water recovery targets.
This shrinkage is being done by the state government rather than buying water back from farmers to achieve water for the environment. The shrinkage project also involves building a 270km pipeline to replace the Broken Hill’s water supply from Menindee Lakes 90km away by pumping water from the Murray via a new pipeline. The is essential if the Menindee Lakes are moved to the shrinkage plan because the lakes could no longer be managed to ensure 18 months supply of drinking water to Broken Hill.
The consequence is that there is little reason for the Murray-Darling Basin Authority keep the Darling River flowing below the Bourke weir. Instead the river will be managed for upstream irrigators while the Darling and Menindee Lakes will be left to dry out more often. The lower Darling River will stop flowing and it will become reduced to a series of stagnant pools.