World Water Day

Today is UN World Water Day, an annual celebration of the importance of freshwater. Groundwater accounts for over 97 per cent of fresh water on Earth that is available for use (e.g. not frozen in glaciers and ice caps).

This year’s theme for World Water Day is ‘Valuing Water’. Here, hydrogeologist Jade Ward gives and overview of what groundwater is and highlights three areas of innovation and research in hydrogeology that demonstrate the value of groundwater. Groundwater resources are helping to address worldwide issues such as the global water crisis, waterborne disease and climate change adaptation.

What is groundwater?

Groundwater is often considered a ‘hidden asset’ because it is out of sight, in the ground beneath our feet. Found within rocks, in fractures and in tiny spaces (pores) between rock particles, groundwater accounts for 30 per cent of all fresh water on Earth and over 97 per cent of fresh water that is available for us to use. The vast majority of water on Earth is found in the oceans and most fresh water is locked up in glaciers, ice caps and snow.

Groundwater and the global water crisis

The world is currently facing a global water crisis, with the combined pressures of climate change and population growth leading to drought and water shortages on a more widespread, frequent and severe scale than previously experienced.

Groundwater is naturally stored in the ground, in rocks called aquifers. This natural storage provides a buffer to climate change impacts. For example, in times of drought river flow reduces and is naturally sustained by groundwater baseflow. In regions with highly seasonal rainfall, rivers often run dry, but groundwater is often still be available to use. With climate change expected to increase the magnitude and frequency of extreme weather events, it is predicted that more regions of the world (including the UK) will have to cope with more extremes in climate variability. Groundwater will be a key resource in adapting to these changes. Groundwater research is helping scientists to understand more about droughts, and the role of groundwater to build resilience of water supplies. 

Groundwater and combatting waterborne disease

At least two billion people worldwide use a drinking water source that is contaminated with faeces (WHO, 2019). Groundwater quality is typically less likely to be contaminated with microbial pathogens than surface water, because groundwater is naturally filtered as it moves through the aquifer. This generally reduces turbidity (the cloudiness of the water) and pathogen transport. This is especially important in areas where there is no treatment available for drinking water, for example in low- and middle-income countries.

However, not all groundwater sources are free from microbial contamination. If the borehole is near to a contamination source or is not well maintained (or both!) then contamination can occur. Monitoring groundwater quality is important to measure progress towards UN Sustainable Development Goal 6: safe access to water and sanitation for all by 2030. Jade’s PhD research focused on investigating new methods of detecting microbial contamination, to see if we can improve water quality monitoring. Recent developments are focusing on improving the speed and accuracy of results.

Even if groundwater quality is good, groundwater sources still need to be managed sustainably to continue to provide water, including consideration of potential climate change impacts, and the best way to maintain water infrastructure.

Groundwater for low-carbon heating

The UK is the first G7 country to sign up to a legally binding net zero carbon target. This is a significant step towards mitigating the impacts of climate change. Groundwater heat pumps could offer a low-carbon alternative to traditional carbon-intensive heating systems, which could help the UK to reduce carbon emissions. Groundwater is used to heat a liquid refrigerant to become a gas, which links into a building heating system. Mine water geothermal energy is a current research topic in the UK. It is important to understand the sustainability of such systems, potential issues that might arise and how to deal with them, and how to ensure environmental protection. Economic and regulatory aspects also need to be considered if this is to become an affordable technology.

Groundwater is already a valuable resource and it is going to become more important in tackling climate change and ensuring water security around the world. It’s really important that we understand where our water comes from, the benefits of using groundwater sustainably, and how to protect it. The theme for UN World Water Day 2022 is ‘Groundwater: Making the Invisible Visible’, which will raise awareness on a global scale. Look out for more about this in future blogs.

Find out about all the groundwater research going on at BGS and follow the groundwater team on X @BGSGroundwater.

About the author

Jade Ward was a hydrogeologist at BGS and worked on a range of groundwater-related projects.

Find Jade online:
LinkedIn | @thewaterscientist