Queensland's Liberal National Party has thrown its support behind a reimagined plan to take "excess" floodwater from north Queensland, to provide drought-relief in western and southern parts of the state.

Known as the New Bradfield Scheme, it is based off an original plan from the 1930s, to divert floodwaters from the north down to Lake Eyre, using dams, pumps and pipes.

Tellingly, the original Bradfield Scheme never got off the ground, with governments over the generations rejecting its viability on economic, scientific and engineering grounds.

But the LNP is hoping its revitalised plan will be a vote winner and offer a "vision for the future" heading into next year's state election.

So what would the New Bradfield Scheme look like and could it work?

What is the Bradfield scheme?

Engineer John Bradfield first devised the Bradfield Scheme in the 1930s, with the aim of using a hydraulic system of dams, pumps and pipes, to send floodwaters from the coastal rivers of northern Queensland inland and across the Great Dividing Range to Lake Eyre.

Under the scheme, water from the north would be diverted inland to grow crops such as rice and cotton. ( Supplied )

The general premise of the New Bradfield Scheme remains the same, but the LNP has proposed some major operational changes to increase its viability.

Water would be drawn from the South Johnstone, Tully, Herbert and Burdekin Rivers, into the Hell's Gate Dam in north Queensland.

The height of the dam would be almost doubled to increase capacity and allow natural gravity to take the water, through tunnels, to its next location.

The water would be fed under the Great Dividing Range into the Warrego River in southern Queensland.

It would also be used to irrigate agricultural land south and west of Hughenden, to build a new food bowl.

The LNP hasn't released any predicted costings for the scheme, but the party has committed $20 million to fund a CSIRO feasibility study.

How does the new plan differ from the original?

The theory behind the original Bradfield Scheme was that increasing irrigation and sustaining bodies of water in central Australia would ameliorate the climate, leading to increased rainfall, an expansion of fertile farmlands, greater agricultural production and food exports, and the creation of additional jobs.

That theory has largely been debunked over the following 80 plus years, but the new proposal does draw on some elements of the first plan — namely providing drought relief and driving agricultural production.

Instead of floodwaters being funnelled to Lake Eyre, the LNP's revised scheme would see the water travel into the Warrego River in south-west Queensland, which is a catchment within the Marry-Darling Basin.

Bradfield theorised that re-directing floodwater to places like Lake Eyre — seen here with water in 2015 — would improve inland Australia's climate. ( Supplied: Matt Wedge )

The LNP said the water would be reserved for use by southern Queensland farmers.

The LNP's plan to raise the height of the Hells Gate Dam also eliminate the original challenges of sending water over the top of the Great Dividing Range.

In theory, the water would be fed by gravity, through tunnels, under the range down into the Warrego.

The LNP also said the New Bradfield Scheme would "use water from the largest dam ever built in Queensland to create a new food bowl on the western side of the Great Dividing Range".

The party argued the water would be used to irrigate around 80,000 square kilometres of black soil plains to the south and west of Hughenden — an area substantially larger than Tasmania.

Could the Bradfield scheme work?

Bradfield continued to push his proposal until his death in 1943 but the viability of the original scheme as an irrigation plan has been dismissed many times by experts over the past 80 years.

The scheme has been rebutted on scientific, engineering and economic grounds.

A major point of criticism regarding the Bradfield Scheme has been the estimated cost of implementing it.

Bradfield had put the cost of his revised scheme in 1941 at "up to GBP $40 million", which translates to approximately $3.2 billion in 2018 prices.

It's estimated the New Bradfield Scheme could cost upwards of $15 billion and take more than a decade to construct.

Environmentalists had also previously been concerned that diverting floodwaters away from their natural paths could affect the ecosystem.

It could cause wide movement of invasive species, collapse marine and estuary ecosystems, and even cause economic damage to coastal communities, according to experts.

But the scheme has also had its strong supporters.

On April 11, One Nation Senator Pauline Hanson kicked off her 2019 Federal Election campaign with a media release that promised: "We will build the hybrid Bradfield Water Scheme and drought-proof much of the country, while solving the issue of water for the Murray Darling."

Earlier this year, former Deputy Prime Minister Barnaby Joyce said building the Bradfield Scheme to redirect water is the one thing Australia can do to reduce the effects of drought.

The LNP's New Bradfield Scheme was devised by former Queensland policy stalwarts, Sir Leo Hielscher and Sir Frank Moore.