In the 1960s, Ian Stevenson used to wander down to the grassy banks of the Murray River after school or on weekends to throw in a line, hoping to catch a feed of yellow-belly or redfin.

Occasionally he, or more often his dad or uncle or grandfather, would catch a Murray cod.

"Pa, Uncle Herbie and Dad started with handlines, we [kids] used to have fishing rods," Ian said.

A young Ross with a haul of fish from the river. ( Supplied: Ross Stevenson )

"[Uncle Herbie] caught a huge cod, nearly a hundred pounds — so just under 50 kilos."

Ian was a third-generation Mildura kid, raised on stories of the "mighty Murray River" from his parents and grandparents.

His cousin Ross, 10 years older than Ian, was the same.

"The Murray, I get goosebumps thinking about it," Ross said.

"I was born and bred on the Murray — [for] my parents it was their life — their grandparents and a lot of my mates are the same."

But the river that Ian and Ross spent their childhood on was already very different to the one their parents told them about. And it was changing before their eyes.

Overfishing devastated local fish populations in the 1800s.

Then carp turned the "crystal-clear waters" to mud during the 1960s and early '70s.

And then there were the dams, weirs, water diversion, and irrigation.

Ian said he saw many of the lakes slowly shrink, and the water levels on the river drop during his childhood.

A newspaper clipping of Herbie Stevenson with a giant cod caught in the Murray. ( Supplied: Ross Stevenson )

"The complete lack of compliance — people had permits to take too much water anyway and then they were taking huge amounts on top of that," he said.

"My uncle Herbie, he's 92, he's lived in Mildura his whole life, and he gets visibly upset when he talks about it because it can hurt ... someone like him who was a fisherman and enjoyed the environment, it just changed so dramatically.

"We used to accidentally catch turtles once or twice a year, then they all started to disappear.

"There was a native catfish that no-one else liked except my Nana used to eat them, and they were starting to disappear around the same time as well."

While Ian and Ross don't think the dams themselves are the issue, they say they saw the impacts of too much water being allocated to irrigation first hand.

And Ian is frustrated that scientists and politicians don't seem to be too interested in the oral histories of the river.

"With Indigenous heritage and some memory heritage, you can't get too scientific about it, [but] any evidence is valuable I think."

Australian rivers need floods

Dammed rivers usually show signs of distress towards the mouth, where dredgers may be needed to keep them from silting up. ( Carl Curtain )

Damming rivers is a bit like putting a tourniquet on a limb.

The extremities — river mouths — tend to show the first signs of distress.

Because the amount of fresh water flushing out to sea is reduced, the marine environment starts to push its way up river, wetland and river management expert Richard Kingsford from UNSW said.

Many big old trees along the Murray have died. ( Andrew Chapman: Old Parliament House )

"You get what is called a 'salt wedge'," Professor Kingsford said.

"There's not enough fresh water to keep the coastal marine systems at bay, so it becomes more and more marine, and that affects a whole range of people, including irrigators up the river, depending on how far that salt wedge gets."

Species that inhabit rivers in Australia have evolved to depend on variable river flows.

River flooding triggers blooms of invertebrates, bacteria and plants, and many species move onto floodplains to spawn or to spend the first years of life.

"You get this huge pulse of productivity, a lot of our invertebrates and plants are lying in the soil ready for that flood to germinate or hatch," Professor Kingsford said.

In 1978, Ian's dad took him around to show him how salt was building up along parts of the river.

That was a symptom of flow control, and not enough big flushing events. Further along the river, big redgums too were starting to die.

Who pays and who profits?

The Ord River irrigation scheme hasn't recouped its investment, according to the Australia Institute. ( ABC )

In New South Wales, a $1 billion promise from the state and Federal Government of more and bigger dams on the Lachlan and Peel Rivers carries with it the allure of a drought-resilient future.

But if the Murray-Darling has taught us anything, it's that dams can be an expensive gateway to regret, Quentin Grafton told ABC RN earlier this month.

Instead, we need to be asking who are the real winners and losers from redirecting our river flows.

"Someone is paying for those dams if they do get built, and it's going to be the taxpayers of Australia," said Professor Grafton, chairholder of the UNESCO Chair in Water Economics.

"This is not about storing large amounts of water for communities, it's about storing water for irrigation purposes.

"It does stack up for the irrigators or the farmers ... they clearly benefit, but there's no benefit here in the national interest or the public interest. In fact, it's just a waste of money."

Most dams don't make economic sense, and only benefit a few big irrigators at the expense of the taxpayer, according to Professor Grafton.

"You do the cost-benefit analysis on some of these dams...one of the largest dams we have in Australia is in fact on the Ord River," he said.

"That scheme there, which has been in play for decades now, for every dollar that was spent by the government, they got a 17 cent net return. So in other words [taxpayers are] out of pocket over 80 cents per dollar spent."

Supply creates demand

Supply creates demand, and problems down the track when supply runs out. ( AAP: Dean Lewins )

The problem, according to Professor Grafton, is that building new dams creates more demand.

When more water is available, it is quickly allocated as irrigators increase their usage or bigger operators move in.

And once we increase demand and dependence on a system, it's very difficult to turn back.

The Chaffey Dam near Tamworth was at around 95 per cent capacity in late 2016. Three years later it's at critical levels.

Last Tuesday, Tamworth councillor Mark Rodda called on the local council to ask the water minister how the dam was depleted so quickly.

His motion was defeated seven to one, with other councillors saying it was time to focus on the present and future, not the past, according to local media reports.

But learning from the mistakes of over-allocation should be the first step in working toward water security, according to Professor Kingsford.

"The issue of towns running out of water is an issue of poor priority setting," Professor Kingsford said.

"We had a lot of water only three years ago, but that's all gone and towns are running out of water. If you better looked after your towns as a priority and said, we've always got to have five years' worth of water or 10 years' of water for our towns [we wouldn't be in this situation]."

Ross and Ian agree.

Ross doesn't think most farmers benefit either.

When water levels dropped around Mildura during the millennium drought, he said most small irrigators couldn't afford to keep buying water.

"The rich that could afford to buy extra water in at quite exorbitant prices, their fruit blocks survived really well," he said.

"The poor little fella who had about 50 acres, they couldn't afford to buy water in. They had just enough for two or three years to keep their vines alive, that's it."

Ross thinks the only way back for the Murray-Darling now is for the Government to buy back water allocations.

With the amount of water allocated along the system now, he doesn't think it will every be able to properly flood again — there are so many dams to fill along the way.

"When you get a big season of rain, all it does is fill up the dams, and the natural ecosystem doesn't get filled up," he said.

"It would not be easy, because you've got those big multi-national corporations, you've got blokes that are buying water and trading it like it's on the stockmarket.

"There's enough water storage there — if they got rid of cotton, got rid of rice, and halved the amount of almonds ... it was very short-sighted and greedy of these governments to sell all that."

Selling up and moving on

Demand increases when supply does, and creates future problems according to experts. ( ABC News: Michael Vincent )

Ian left Mildura fairly early on to pursue work.

Ross stayed behind and eventually bought himself a fruit farm.

But as more and more water licenses were being sold, he said he saw the writing on the wall.

He sold up his farm, and moved away from the river just before the millennium drought.

"I was lucky enough to sell it off just before the shit hit the fan," he said.

"You could see the problem was coming. There was more and more land being OK'd for development, the almonds had just started.

"We've got a lot of family and friends still up there. I thought, all our hard-earned money we've earned over the years, I don't want to end up penniless just because the Government couldn't get their acts together."

"I feel more comfortable — I can support my family down here."

While it's tempting to fall for the logic that building more dams means more water for farmers, especially during drought, it's just not the case according to Professor Kingsford.

"My view about that is we're always going for the supply side of the equation — so we're saying we're running out of water let's get some more — it's a magic pudding sort of approach," he said.

"I think we can do a lot more with the water we've got if we're more efficient.

"It means some major changes in terms of a switch away from a focus on irrigated agriculture being the priority."

That switch needs to happen sooner rather than later, Ross said.

"I could be seen as a pessimist, but my own opinion is if the Government don't get its act together and undo what their predecessors caused, one day you might have a 10- to 15-year drought, and it won't just be the little towns along the river [running out of water], it'll be South Australia."