So why hasn't a Bradfield scheme been done before? Current and planned irrigation schemes in Queensland follow a more modest mosaic development pattern at locations where favourable topography, rainfall, and soils create local economies. But these schemes periodically run out of water. Few places have dam sites that would allow the full development of a 40,000 ha irrigation scheme which requires 400 GL or more of water delivered to farms every year.
We may have run out of new dam sites near population centres. After working with northern jurisdictions, research partners and communities for over 2.5 years, the Northern Australia Water Resource Assessment (NAWRA) identified the catchment of the Mitchell River in the sparsely-populated far north as the best site for a new scheme. The NAWRA methodology did not consider the option of cheap gravitational conveyance of water long distances to existing communities, supplemented by hydropower generation. Unlike the far north, the communities of the Mitchell Grass Downs have the culture and infrastructure for rapid expansion and value-added returns on investment due to town and mine water supplies.
The current plan for Hell's Gate provided by a consortium of Townsville businesses, led by the Snowy Mountains Engineering Company (SMEC) has a full supply level of only 372 m AHD and storage volume of 2,110 GL to primarily supply a 50,0000-hectare scheme downstream. Leon and Sir Leo are proposing increasing the height of the proposed dam by 100m to 470m AHD, sufficient for the gravitational conveyance of water over the Great Dividing Range. A large scale hydro and irrigation scheme would generate economies of scale that would help Queensland achieve their renewable energy targets while enhancing agricultural competitiveness on the world and national markets. If not now, at some time the dam wall at Hell's Gate would be raised to full height rivalling mega-dams around the globe. Feasibility analysis of a new water delivery systems cannot be done in the absence of a national or world-wide historical context.
It is recognised that the impact to downstream water flows, interruption of existing road and rail infrastructure, environmental damage from inundation, and costs of construction and operation of the system are vital concerns. While the engineering feasibility of the Bradfield Scheme would be similar to the Snowy Mountains Scheme, ongoing studies by water experts have yet to determine the potential of specific options.
When ex-prime minister Malcolm Turnbull revealed plans for a $2 billion expansion of the Snowy hydropower capacity by 2 gigawatts of pump storage he declared "This is the next step in a great story of engineering in the Snowy Mountains and the courageous men and women who are confident and committed to Australia's future." Mr. Turnbull's comments referring to Snowy 2.0 are equally applicable to a Bradfield Scheme. With both popular support and the support of the high-profile politician Barnaby Joyce, and minor political parties Pauline Hansen's One Nation and Fraser Anning's Conservative Nationals, a Bradfield Scheme is shaping up as a wedge issue to draw votes away from the major parties, unless the major parties platform some version of the scheme before the next election.
A scheme generating the agricultural revenue of the Murray-Darling Basin, the renewable power of the Snowy Mountains Scheme, flood water control to save the Reef, and mitigation of flood damage to environmental, personal and public assets is highly desirable. Due to situational and environmental constraints, water conveyance may be the most practical way for Queensland to increase land under irrigation profitably. A gravitational Bradfield Scheme is the inevitable outcome of a development process that puts the priority on reduction of carbon emissions, conservation of the environment, and sustainable development.
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