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Groundwater series part 1: Groundwater and the work of hydrogeologists

The groundwater series was put together by Luisa Andrade, a PhD researcher based in UCC. Her project is

co-funded by iCRAG and the Geological Survey Ireland, and looks at microbial contamination of groundwater resources, specifically those used for drinking, in Ireland. Luisa graduated in Civil Engineering with a focus in Environmental Engineering from Universidade Federal de Pernambuco, in Brazil, where she is from, with one year of her undergraduate completed in University of Adelaide, in Australia. Before starting her PhD, she also worked as a Research Assistant in University College Dublin on a project that looked at groundwater contamination caused by floods.

Our planet’s surface is mostly covered by water (over 70%!), but just a mere 0.75% of it is available for us to use as freshwater. That is because the salty ocean waters need to be desalinised (have the salt removed) before use, which is very expensive, and the freshwater stored away in ice caps cannot be easily accessed. Still, we see freshwater everywhere: coming out of our taps, in rivers and lakes, and in the annoying winter rains. But did you know that other than ice caps most freshwater on the planet (30.1%) is actually stored underground where we cannot see it? Seems strange, but it is true, and that is what we call groundwater.

The geological formations that store groundwater underground are known as aquifers (see Figure 1), and there is a lot more happening in them than we may think. Water in aquifers can move upwards, downwards and sideways at higher or lower speeds, and many chemical reactions can take place there also!

Figure 1: Illustration of groundwater flow in an aquifer

Groundwater plays a big part in our lives, from the water we drink to the water used to make clothes, grow food, and even generate electricity. So, it is very important to understand things like how the water flows underground, how groundwater interacts with surface waters, and which chemicals and microbes are present and how they got there. To investigate all of that, we can count on a particular type of geologist that studies groundwater: the hydrogeologist (hydro=water, geo= earth or ground, logia=science or study of, so hydrogeologists can be translated to mean “people that study water in the ground”). A hydrogeologist’s work can involve a lot of time “in the field” taking measurements, time in an office analysing maps and measurement results, developing hydrogeological models or producing reports, and also time in laboratories analysing groundwater samples (see Figure 2 for some examples). Hydrogeological studies are incredibly important, as they allow us to understand and avoid groundwater contamination, supply water to areas where surface waters are not available, and safely extract water from aquifers without causing them to dry out.

Figure 2: Pictures showing some hydrogeological work. A) inspecting a well, B) taking field measurements, C) analysing groundwater samples in the lab, and D) measuring the groundwater’s pH in the field.

Now that we know a little more about groundwater, make sure you check back to find out how groundwater is safely extracted and used in our next post!

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