Greater/wider water distribution & associated moisture in/on the ground will also reduce bushfire incidence. Small lakes all over the place will provide fire-fighting supply. More water means less fire = healthier fauna & flora & more likely than not a healthier economy.
Inland Australia would become closer to what it used be with more water. As Canem Malum says; strategically placed explosives would do the job. It would improve Nature as more areas of cooler ground would prevent a lot of heat rising & on & on is the list of benefits from irrigation. We don't need huge dams, only more moist ground. Use whatever water flow there is to drive pumps as well as wind mill pumps. All very little energy requirement for such a network.
Just some forward thinking/vision by all is all that's needed.

One of the ‘benefits’ of irrigation is a rising salt table and all the associated detrimental issues.

is a rising salt table
Is mise,
How so ? Freshwater floats on saltwater. The more freshwater there is the more saltwater is kept down. I have actually displaced saltwater with freshwater in an old well.

Basic chemistry, fresh water mixes with salt water and the salt table rises, it’s not like oil and water.
Australian agricultural land is being affected at this moment.

Just Google ‘rising salt table’

Basic chemistry, fresh water mixes with salt water and the salt table rises,
Is Mise,
Even more basic is the fact that when you replace saltwater you're left with freshwater. What Google refers to is when freshwater injection is only temporary !
On-going irrigation with freshwater will gradually reduce salinity until totally displaced.
I think you're confusing irrigation with pumping out freshwater without replacing it.

Canem Malum, this rain event lasted 6 days, dropped between 600mmn & a meter of rain on most of the entire area from the NSW boarder to Maryborough, 360 kilometers of Queensland, then a couple of hundred kilometers further south into NSW. This following a very wet spring & early summer. Maryborough & Gympie both had minor floods a couple of weeks ago.

Every river, every creek & every little depression in the ground was full of water, there was no where to divert any run off to anywhere else. It was just pure luck that the majority of the rain stayed east & south of the Wivenhoe catchment until the last 30 hours, or it would have been a lot worse. Much of this flood is from runoff from below the dams, & the Bremer river coming in at Ipswitch from the south

Some areas around here, 60 kilometers south of Brisbane are only reaching their peak to night. Now we have a forecast of 40 to 80mm of rain tomorrow, & another 50 on Friday. This wont renew the main floods, unless a couple of big thunderstorms form & drop a real deluge, but will delay any reduction of existing water. My little river was 28 meters deep, 4 meters deep for 400 meters across my bottom paddock & almost a kilometer wide on the other side.

It & the Logan river are flooding far southern suburbs of Brisbane 65 kilometers south of the Brisbane river floods.

There is absolutely no where to send any of this water, unless you bulldoze the flooded area of Brisbane, & the Waterford Beenleigh area, to make them a water course. Not sure the flooded residents would agree to that.