3 min

Making the invisible visible: uncovering groundwater with data

In the Netherlands, where Kiwa is headquartered, water is everywhere – in canals, lakes, rivers and seas. Yet like in many other countries, the water supply is under pressure. This is because almost all of the world’s liquid freshwater – about 90 percent – is hidden under the ground.

World Water Day 2022 – held on 22 March – focuses on this invisible resource. Groundwater is an essential source of drinking water around the world. In Europe, one in every four glasses of drinking water come from groundwater sources, such as aquifers. And about half of the groundwater extracted is used in agriculture, with other users including the manufacturing and service industries.

We need huge volumes of water to keep people healthy and run today’s economy. But it is important to remember groundwater is a limited resource. As UN Water urges, “Groundwater may be out of sight, but it must not be out of mind.”

What is groundwater?

“Groundwater is important because it’s the main source of liquid freshwater in the world,” said Dr. Elisabeth Lictevout, Director of the International Groundwater Resources Assessment Centre (IGRAC).

Elisabeth is a hydrogeologist and has been working around the world for almost three decades. Before moving to the Netherlands in early 2022, she spent ten years in Chile, including five years in the Atacama Desert – the world’s driest desert. “It's a real desert – all is mineral, and life is so scarce” she said. “But there are hundreds of meters of groundwater below your feet.”

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Photo: Elisabeth Lictevout from IGRAC in the Atacama Desert, Chile.

Groundwater is liquid water held underground in geological formations like aquifers. It flows like rivers, but much more slowly; where the water in a river can cover a certain distance in a day, it might take groundwater decades to cover the same distance. Groundwater is often less contaminated than surface water, as it is filtered through the ground. It is also protected from evaporation.

Groundwater: a limited resource

However, groundwater is not always a renewable resource. It can take hundreds or thousands of years for the water that falls as rain to flow into groundwater, through the ground, to a spring and out of your tap. This makes groundwater an excellent buffer against drought and climate change: In times of drought, if there is no rainfall for months or even a few years, groundwater supplies can provide the water we need. But when depleted if over extracted, it can take decades or even centuries to recover. 

“When you start seeing problems in an aquifer, it means that the pressure on the resource likely started many years ago” Elisabeth said. “This is why groundwater is an incredible buffer against drought, and also climate change, but, on the other side, over extraction or exploitation of the groundwater may lead to a point of no return, at least at the human timescale.”

It is difficult to get an accurate picture of just how much pressure people are putting on groundwater by extracting it globally. We know humans are having an impact, but without real-time real-world data, it remains difficult to assess that impact and plan accordingly.  The risk is high, as Elisabeth explained. “There is not only the problem of groundwater levels going down but also contamination of groundwater. For example, if seawater intrudes groundwater (because of over extraction of groundwater) then the groundwater is unusable for most uses, and it costs a lot to remove contamination.”

It is especially challenging to assess and manage groundwater resources that lie under country boundaries – transboundary aquifers. When more than one country or jurisdiction has access to a single aquifer, agreements need to be put in place to ensure shared responsibility, use and management. There is still too little experience and too few examples of cooperation on transboundary aquifers; there is a lot of work to be done, and it all starts with data.

Data collection challenges

“Despite all of today’s challenges, like climate change and water availability, we still don’t have enough real-world data to plan our water use effectively,” Elisabeth said. “Groundwater is especially difficult to monitor, and that’s one of the challenges we are addressing at IGRAC.”

There are technologies like satellite mapping and highly sophisticated models for estimating the volume of groundwater. IGRAC has been producing maps of groundwater since 2012 – transboundary groundwater in particular, with the latest update in 2021.

“If there is not enough data, information and knowledge about groundwater, we will not be able to prevent over-extraction and manage the resource wisely,” Elisabeth said.

Water management practices could include alternating sources depending on water availability, she explained. “In rainy years, you can use surface water and let the groundwater recharge, and in dry years, when you don't have so much surface water, you can use groundwater. But this need to be planned; you can only manage it if you have information.”

Groundwater is not always invisible –sources and wetlands are fed by groundwater. In limestone caves, for example, it is sometimes possible to see the groundwater. But to get accurate, direct data, you usually need to drill a borehole. Elisabeth says generating data – direct and indirect measurements– then sharing the data and transforming it into information that can be used for water management will be key to protecting this hidden resource.

“When you next pour a glass of water, take a moment to think about whether it came from a groundwater source,” Elisabeth said. “Keeping this precious resource in mind – making the invisible visible – will help us protect it for the future.”

Innovation in monitoring groundwater

One example of a monitoring tool is called Menyanthes. In 2006, researchers at KWR Water Research Institute and the Delft University of Technology built a tool to monitor groundwater in the Netherlands and provide data to help the Ministry of Transport, Public Works and Water Management and the National Institute for Coastal and Marine Management safeguard at-risk habitats.

Researchers Jos von Asmuth and Kees Maas and their teams built the monitoring tool – Menyanthes – to process and analyze their observations of groundwater levels. The tool, which is based on MATLAB, was designed to provide hydrogeologists and ecologists with data, by supporting the whole process, from acquiring the measurements to visualizing the modeling results.

Kiwa’s work with groundwater

Dragan Jovanov, head of the Kiwa Group’s water business sector, commented: “Through innovative data-supported solutions, Kiwa aims to improve visibility in the marketplace and provide confidence and meaningful insights to all stakeholders active in the water industry.”

Kiwa has a long history of working with water. As groundwater is such an important and widely used water source, Kiwa has an important role in ensuring its quality. Kiwa CMT tests groundwater for the construction and water distribution industries.

Dragan continued: “The requirement for groundwater testing can be far-reaching, and it can be needed due to environmental or geotechnical reasons, to qualify or quantify issues relating to construction, distribution or infrastructure. Kiwa’s services in this area include automated groundwater datalogging, traditional groundwater level monitoring, and groundwater sampling and testing for a number of contaminants and minerals.”

To find out more, visit the Kiwa website.