DARLING River at a low ebb.
DARLING River at a low ebb. Max Phillips

YOUR SAY: The enigma of the Darling part II

THE Menindee Lakes are a chain of nine shallow and usually dry, ephemeral lakes.

They have a surface area of 457sqkm (eight Sydney Harbours), but only average a depth of 7m. Even though their capacity is 1750GL they are not considered reliable because of their sporadic water intake and high evaporation rates.

To guarantee Broken Hill's water supply a sophisticated system, completed in 1968, was developed to divert water to the lakes from the Darling.

But because they were considered unreliable, a pipeline completed in 2018 was constructed from the Murray at Wentworth to Broken Hill.

The pipeline made the lakes redundant. What to do with their water became a bun fight between the Green environmentalists, the farmers, the MDBA, the state and federal governments and common sense.

Of the options were:

1. Disconnect the lakes from the river and allow them to return to their natural mostly dry pre-1968 state.

2. Use the existing infrastructure to top them up, without returning any water to the river. As any input would evaporate this is considered, by some, to be wasting water.

3. As for Option 2, but release some water to the river to be used anywhere in the system.

4. As for Option 3, but require all the returned water to be used exclusively and judiciously in the lower Darling.

5. Expand Option 4. The Darling has a gentle gradient and a deep U-shaped river bed. One suggestion has been to build a series of weirs across the channel. Each would back up water for many kilometres.

Their primary function would be to stop the river rapidly emptying after rain events, and retain water in the riverbed. The weirs would allow floods to go over the top, have low-level valves to keep water moving downstream and fish ladders.

The GEs wouldn't like Option 5. Multiple weirs across the Darling! OMG! "Good Gaia no!" But do they have a better alternative?

Surprisingly the change from lakes to pipeline resulted in protests from the lower Darling community about what would happen to the lake's water. Their angst was about Option 3 which would allow the water to be used anywhere in the system. So, what has happened to date?

In 2016, Nick Xenophon said if South Australia was given an extra 450GL, to "freshen up" the estuarine Coorong Lakes, he would support a crucial government bill.

The Government agreed and they were supported by GEs because they believe the Coorong Lakes are fresh, they've always been fresh, and they need refreshing!. Actually, they haven't been fresh since the end of the last Ice Age 12,000 years ago and definitely not during the last 200 years.

This is supported by the fact that ocean-going vessels have sailed across Lake Alexandrina to Lake Albert and ports in the Murray for the last 150 years. There's even an 1878 lighthouse on Point Malcolm to guide them.

Leonie Blaine (11/02) doubted the state and federal water ministers and the NSW Irrigation council who said it was the drought. They were correct.

Nor was it the farmers' and irrigators' fault either.

In this particular case the main culprit was the SA Government who usurped and wasted the water, while the lower Darling farmers and environmental areas didn't get any and the Menindee fish went belly up.

Leonie also mentioned water theft and meter tampering, which I agree is inappropriate, but may have kept withering crops alive.

But it is also inappropriate, and morally worse for the GE's to waste vast amounts of water with their over-the-bank watering, freshening the Coorong, and not allowing dams and weirs to be built.

Maybe it's time to replace the MDBA with a group who are independent of the farmers, the GEs and the governments to develop a plan, which is practical, flexible and a fair solution for all.