There are several types of water in the world, depending on its source, composition, location, etc. The oceans, rivers and lakes are the sources of human activities and the supply of drinking water to their populations. Many people do not know well what are the waters underground, as they are extracted and can be drinkable for human beings.
For this reason, we are going to tell you in this article what groundwater is, what its characteristics are and its importance for the human population.
What is groundwater
Groundwater is a natural freshwater resource found on the surface of the earth's crust. They are usually found in impermeable geological formations called aquifers. Groundwater plays an important role in human activities and the maintenance of ecosystems.
The Food and Agriculture Organization of the United Nations (FAO) defines this type of water as the water that is found below the surface and occupies the pores and cracks in the rocks. Groundwater is stored in places where the water is kept at a constant temperature similar to that of the area in which it is located. These places are called aquifers and they are geological formations made up of several porous and impermeable layers that can store fresh water underground.
In some cold regions, this water is often frozen. Instead, in arid or semi-arid regions, they constitute the only source of fresh water in the region.
Another key point of groundwater is its fundamental role in the hydrological cycle. On the one hand, rainwater seeps into rivers and lakes and reaches the surface in the form of springs. On the other hand, another part of this resource filters to the earth's surface and reaches the aquifer, where it can remain for many years. Also, some of this groundwater flows through the ground and into the ocean, keeping the water cycle in balance.
How is groundwater formed?
Groundwater is produced when precipitation seeps through soil pores. This precipitation can be rain or snow.
Groundwater is formed when rainwater falls to the ground and some of the water flows through surface streams into rivers and lakes. However, another part of this precipitation wets the ground by infiltrating it. This filtered water is collected in so-called aquifers.
This type of water can hide for millions of years, and depending on its depth, it is more or less easy to locate and access it. Also, they are useful for industry and agriculture, and are capable of supporting a wide variety of life forms.
How much groundwater is there on earth?
According to the International Groundwater Resources Assessment Center (IGRAC), the amount of water on the Earth's surface is almost 1.386 million cubic kilometers. Speaking of percentages, we can say that 70% of our planet is water. For more than two thousand years, this number has remained the same: neither decreasing nor increasing.
Of these 1.386 million square kilometers of water, 96,5% is salt water. The amount of fresh water on Earth is only 3,5% of the total. Ninety percent of these resources are found in the frozen state of Antarctica. Of the rest, only 0,5% of fresh water is found in subsurface sediments, and the rest (0,01%) is found in rivers and lakes. Therefore, the amount of groundwater on Earth is very small compared to the amount of water found in Antarctica.
They are currently overexploited and contaminated by human activity, This poses serious problems to the populations that depend on these waters. Water is withdrawn from these sources much faster than infiltration or natural replenishment.
The consequences are significant, as the reduction of this scarce resource can lead to higher production costs or problems with waterways. Also, the water quality of these groundwater sources may be affected. If the situation continues, we may see the depletion of these precious aquifers.
Why is groundwater important?
Groundwater is one of the main sources of water suitable for human consumption for almost half of the world's population. This is explained by the International Groundwater Resources Assessment Center (IGRAC). But more than that, this water is vital for the sustainability of the Earth's diverse ecosystems.
In addition to consumption, groundwater is a valuable resource for agriculture and food. A person can survive with two liters of water a day, but we forget that the food we consume also requires this resource to be produced.
Another focus of our previous review is the important role groundwater has in the environment, particularly in the water cycle. During the drier months, groundwater helps keep rivers, lakes, and wetlands flowing.
contamination problems
However, human activities and climate change are significantly affecting the world's groundwater resources. The overexploitation of this resource or changes in land use explain these decreasing trends in water sources. Likewise, it is worth highlighting urban sprawl and its impact on aquifers.
They warn from the FAO that it is necessary to improve the way we use this resource, mainly in agriculture, one of the sectors that most needs it for development and production.
These and many other reasons make groundwater the protagonist of World Water Day on March 22. It was created by the United Nations to demonstrate its importance in the fight against water scarcity and climate change. Aquifers are seen as our allies in the face of the harmful effects of the climate crisis, so now more than ever it is necessary to protect them.
I hope that with this information you can learn more about what groundwater is and its importance for the planet.