Groundwater is the world’s most abundant freshwater resource and a crucial regulator of water extremes such as floods and drought. But because it is also hidden from our sight, we tend to pay little attention to it. So little, in fact, that we may be destroying it without even noticing.

Groundwater makes up 99 percent of all freshwater that is not frozen. It provides nearly half of the world’s population with drinking water and contributes to about half of the global food production. For some 2.5 billion people in the world, groundwater is their one and only source of freshwater.

But the importance of groundwater is not only a question of drinking water and irrigation of crops. Groundwater is, in the words of the 2020 Stockholm Water Prize Laureate, groundwater expert John Cherry, “the Earth’s life support system.”

Groundwater is essentially the regulator of the freshwater cycle. It acts as a giant sponge that can absorb surplus water and mitigate shortage, making it a vital component in adapting to climate variability. During drought, groundwater sustains rivers, lakes, and wetlands – but only as long as we do not deplete reservoirs, something which we are currently busy doing at an alarming speed in many parts of the world.

In 2015, research based on satellite images from the American space agency NASA showed that many of the world’s biggest groundwater aquifers are being depleted at a much faster rate than they can be replenished. The situation may be most critical in India, which relies on groundwater for much of its food production but where the capacity of 54 per cent of groundwater wells are decreasing.

Groundwater is also threatened by pollution from agriculture, manufacturing and fracking. Chemicals such as PFAS are increasingly found in the drinking water in many countries. But the full extent of this problem is not known, since most countries do not monitor their groundwater. This means that the world’s freshwater may be even more limited than we think.

“Groundwater is the Earth’s life support system.”

John Cherry, 2020 Stockholm Water Prize Laureate

Groundwater governance

Groundwater is often over-abstracted, particularly for irrigation, and its increasing scarcity is coupled with deteriorating quality caused by contamination. It is a complex problem. Not only because groundwater is virtually invisible, but also because many of the contributing factors are thought of as local problems and not as parts of a global threat to groundwater. We can only achieve sustainable groundwater management on a global level with a much more holistic approach.

In places where groundwater resources are relatively abundant and of good quality, they represent vast development potential – a potential which is often overlooked. To fully realize this potential, we need a more robust understanding of groundwater resources and how they are being used and depended upon around the world.

Groundwater as a resource

From a development perspective, proper groundwater management is key to functioning water services and public health, particularly in urban environments. Getting it wrong can have serious consequences.

Most of the urban population growth in the world takes place in slums and informal settlements. In such areas, many people draw their everyday water from shallow wells as this is the most accessible and affordable – and sometimes only – solution. The problem is that urban groundwater is usually exposed to high levels of pollutants.

There are often few, or no, institutions tasked with managing urban groundwater reserves. Such institutions are, therefore, urgently needed to establish well-informed, sustainable practices that also take the interests of vulnerable communities into consideration. Fundamentally, good groundwater management is a prerequisite to fulfilling several sustainable development goals as well as the human right to water.