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Science of Earth-Generated Water

When people are asked Where did all the water on and in the Earth come from? there is often stunned silence.  Most people have not thought why waterfalls and springs flow continuously from the tops of mountains, or why geysers and ocean plumes continuously flow.  However, the answer to this question is fundamental to understanding the science of groundwater sources and providing a sustainable supply for food security.

There is a looming global water and food security crisis, particularly for farming and urban areas.  Rural areas in most countries are under pressure because they do not have access to the large surface water storages of major cities and regional towns.  While some irrigation areas will manage on limited supplies, many dryland farmers have had their groundwater supplies cut, and this water is often the main source of water for their enterprise.  Most people rely heavily on surface water supplies that will always be limited, and perhaps become increasingly polluted.

Undoubtedly, nations must become more efficient at water use and minimise water wastage.  Also, there is a pressing need to make water more potable (drinkable) and therefore make existing water supplies more sustainable and useable.

These strategies alone will not secure the water reserves that economies need for nation building.  However, there is a source of groundwater that is available for all and yet is not part of national, state, and local government plans.

Groundwater systems have been forming below the Earth’s crust for more than 4 billion years, a process best described by former Monash University vice-chancellor Professor Lance Endersbee in his book, A Voyage of Discovery.

It is this perpetual process that created the oceans, the hydrological cycle, the rivers, and the layers of buried groundwater systems in ancient, buried sediments and rock fractures. These buried groundwater systems in the crust are also dynamic due the Earth’s continuous expansion process and associated volcanic and earthquake activity.

There are small-scale groundwater systems (from metres to hundreds of metres below the surface) to large complex systems, sometimes spanning kilometres of galleries and fissures below the Earth, and often more than 300m under the surface.

For the extraction of deep groundwater for urban residents and food producers, the focus is on the confined groundwater zone between 250-500m where sustained yields can vary from 50,000 – 250,000 litres per hour (1.2 – 6 megalitres per day) and which are continuously recharged from the deeper layers of this fractured rock groundwater system.

Most groundwater drillers (possibly more than 95 per cent) are accessing water from the shallow, alluvial sediments (40-80m) or unconfined fractured rock systems up to 200m. However, these shallow groundwater systems are affected by drought conditions, where they are directly connected to inflows from the hydrological cycle (often over months and years).

There is ample groundwater available to drought-proof every food producer in Australia, along with regional cities and towns.  The only limitation to accessing this deep groundwater is the poor public science understanding of groundwater systems.

Consequently, there is a lack of political will to include this deep groundwater in a national water and food security plan. We do not have a crisis in groundwater supply, we have a crisis in groundwater science.

Additional information about the science of deep groundwater sources and exploration can be obtained from the Groundwater Papers section on this website.