Bradfield made his assessments on poor data. Since his time much more detailed and accurate information has become available on topography, precipitation and streamflow in the source areas under consideration; and evaporation rates in areas targeted for reception of water. Even early post-war, engineer Nimmo took a serious consideration to this information and showed the scheme to be not feasible.
The upper Tully River has minimal annual flow for the purpose envisaged; the Herbert above its gorge has an intermittent flow of any real consequence. The Burdekin, at a lower elevation, has more water than the above; but depriving the cane growers on the Burdekin delta of groundwater replenishment might cause some angst.
Rather than asking for reasons why the Bradfield Scheme won’t work; it is more appropriate to ask for credible data to be provided by those supporting it. As it is to ask for the ultimate purpose of ending growth from proactive advocates of that

colinsett,
so, you're saying that getting water into the interior would not be beneficial ? If the Tully isn't sufficient then there are many other sources. Just because some engineers can't figure it out doesn't mean others can't. The question here is not just the Tully River but the concept.

No I. What Colinsett is saying is that the Bradfield Scheme is a bit like free energy machines: Plenty of believers, but no supporting science and no working model.

A shame to see people sucked in by such bunk, especially when there are so many promising technologies being developed.

Fester,
When lake Eyre filled recently there was great hoohah about it. I think it would enhance nature rather than going against it by making the lake permanent. Diverting some flows into the upper catchment would be a lot less complicated than many other irrigation projects.
You wouldn't actually not need diverting the rivers themselves but merely the excess flow from the wet. As for the developed technologies, where are they being implemented ? It's all well & good to have the technology when the mentality to use it wisely is lacking. Suppose it's much better to flood Brisbane every now & then. The benefits of such a scheme outweigh any opposition to it. It's a long-term scheme not something to please the five minute shareholders.