<i>Illustration: Michael Whitehead</i>

Illustration: Michael Whitehead

The return of drought in eastern Australia is a reminder that Australia has not yet done enough to secure our future water supplies by protecting our groundwater.

Groundwater constitutes around 95 per cent of the nation's fresh water resource. Besides supporting $34 billion in mining, agriculture and manufacturing industries it also keeps the Australian landscape, including its lakes, rivers and wetlands, alive. It is in short our main water bank: yet we do not fully know the balance, the deposits or the withdrawals.

The National Water Commission Groundwater Action Plan ($105 million) wound up in June 2012. At all levels of government there has been a slow attrition in the expertise necessary to manage our water resources. This has been accompanied by a significant reduction in public investment in both water research and management, which are now close to their lowest ebb in 30 years.

In short, Australia's knowledge and expertise to manage its precious water wisely and well is attenuating - while recent El Nino forecasts suggest the risks of a major drought are rising. The hard lessons learnt in the Millennium Drought, when our cities, irrigation industries, storages, rivers and towns ran short of fresh water, seem largely forgotten. All this is happening at a time in human history when water is coming under intense stress worldwide from rising demand and pollution.

Australia has attributes that can make us a global leader in wise water management. To give just two examples: we have developed some of the world's most sophisticated modelling systems for measuring and predicting underground water resources which, when fully developed and tested, will provide the basis for effective decision making in future. And we are pioneers in the art of managed aquifer recharge - or water banking - in which water is stored underground during times of plenty and can be pumped up again in times of scarcity. These water banks have been tested around the continent in places such as the Bowen and Namoi basins (for agriculture) and in cities such as Adelaide and Perth (for horticulture and urban watering). They work.

An underground water bank has one huge advantage - unlike a surface dam, water loss by evaporation is minimal. In a country like ours, where evaporation rates often exceed rainfall, this is a vital consideration. It has the added plus of not drowning landscapes, avoiding the clashes so often seen over surface dams. If ever there was an infrastructure challenge worthy of Australia's mettle it would be the development of a network of large ''underground dams'' to conserve surplus water for the dry times we know are on the way.

There is, apparently, a plan to build 100 surface dams in northern Australia to unlock development - but if these dams are on the surface, most content will be lost into the sky. In effect, evaporation means we will have to build twice as many as we need. If the water could be stored underground, not only would construction costs be less - but so will water losses.

Modelling underground water recharge and discharge may not sound very exciting to some but it is an old truth that ''if you can't measure it, you can't manage it''. And Australia is insufficiently equipped to accurately measure and manage its groundwater across the whole continent. Without these sophisticated computer methods we lack the essential tool for effective water governance, one that, like a car fuel gauge, can tell us how close to ''full'' or ''empty'' the nation is at any time.

Together, groundwater modelling and aquifer recharge could position Australia as a world leader in wise water management, as humanity approaches a time of critical global scarcity driven by population growth, overuse and poor management.

This will not only give us a sound foundation for our own future economic and social growth and to mitigate future droughts - but also help us to help our neighbours in the Asia-Pacific region and Africa to avoid their emerging water scarcities and the economic and conflict risks they entail.

Indeed, water expertise could be one of our most potent diplomatic and export initiatives in years to come (just as agricultural aid and trade have been in the past 60 years). All we need to do to achieve this is invest wisely in the necessary science, technology and management skills. Water science and training are not high-cost items, relative to other activities such as building huge dams or ports.

They represent a form of ''infrastructure'' that lasts for generations and only needs topping up, not repair. They pay off immediately in water savings. They provide essential insurance against drought, climate change, and the loss of water-dependent industries, towns and landscapes. They can reduce the economic and social costs of drought greatly.

In a dry land like Australia, we should be saving our water wisely for the future. Let's hear it for a National Water Bank.

Craig Simmons is professor of hydrogeology at Flinders University and director, National Centre for Groundwater Research and Training.