The perennial prospect of ‘turning back the rivers’ in order to irrigate the arid regions of western Cape York, the gulf country and beyond seldom wants for a champion. The blueprint for this scheme, variously described as ‘The Greatest Scheme of All’ and ‘Australia's Next Great National Project’, was drafted by J. J. C. Bradfield, the engineer who amongst much else had input into the design of the Sydney Harbour Bridge and oversaw its construction. Bradfield presented his proposal to the Queensland state government in 1938. In it he advocated diverting west and southwards several rivers whose waters during the seasonal monsoons flowed ‘wastefully’ into the sea. Such a course of action, Bradfield reasoned, would not only bring otherwise excess river water to this region of arid Australia, but would also precipitate climate change. Increased evaporation from the new water sources in formerly arid regions would result in higher annual rainfall. Bradfield anticipated his scheme would dramatically increase primary production, and allow for rapid growth of Australia's population.

Projects of this sort were of much interest to Walkabout, and it is unsurprising that Bradfield was able to promote his scheme in its pages. Writing for a 1941 edition he speculated that in order ‘to hold what we have […] we must have a vastly greater population – say 40 millions 40 years hence. We must plan now how to get these millions’. Although Bradfield's vision was certainly writ large, faith in the transformational powers of irrigation and its supporting infrastructure (such as large reservoirs) is a recurrent theme throughout much of Walkabout, as is a belief in the existence of almost limitless land suitable for irrigation. So too, in one way or another, was the understanding that Australia must ‘populate or perish’. To this end Walkabout can be read for its passion for boosting primary production and rural development, the latter whether through technology, industry and/or population growth, particularly in rural, remote and northern Australia.

Tom Griffiths has described how nationalist anxieties and prophecies played out in debates about environment, population and race, often on a backdrop of central and northern Australia.