Groundwater: What is it and where is it found?

Groundwater can be very useful in agriculture

Surely it sounds like you’ve studied the different layers not only of the Earth, but also of the soil. While it is true that this study is more a matter of geology, certain aspects are very important for agriculture, such as knowing what is the water table and how to take advantage of it. It is a clear example of how different branches of science can help each other.

As you may have already deduced, in this article we will explain what groundwater is and what it is used for, mentioning its usefulness in agriculture and its importance in the field of construction. We will also explain where exactly it is, since the land is divided into several levels. If you are curious about this subject, you will surely find it very interesting. Moreover, knowledge does not take up space!


What is groundwater and what does it do?

The water table is a fairly shallow aquifer

There are different ways to refer to the water table: water table, water table, water table, water table, water table, or just water table. It is essentially a level at which atmospheric pressure and water pressure are equal. In general, the relief of this layer is very similar to that of the normal surface, but it is a little smoother and can emerge outwards by the formation of water deposits.

In other words: The water table is a level in which the underground water is found and whose depth is generally very shallow compared to the level of the ground. You could say it’s a fairly shallow aquifer, as these are usually located in deeper areas. At this level, the interstices between the grains of the earth fill with water, thus saturating the soil. If the layer above is found to be permeable, there could be unsaturated soils. In these cases, the voids also contain air, not just water.

To raise the water table, a reduced and additional water supply is sufficient. In this way, the unsaturated layer becomes a saturated layer. In the event that the thickness of the unsaturated layer, which becomes saturated, is relatively small and, moreover, the topography of the site is adequate, water can reach the surface, becoming visible to our eyes. This is how lakes, ponds and ponds are created. In very severe cases, it can even trigger a flood. This type of surface is called a shallow water table.

Utility of groundwater

Now that we know what groundwater is, let’s discuss what it is for. Well, as you can already imagine, water sources and wells are connected at this level, and the water that comes from it can be drinkable or not. Shallow, these aquifers are the most exposed to the contamination we generate on the surface.

It should also be noted that the groundwater It is very advantageous for most agricultural crops, as long as the depth is sufficient. This will mainly depend on the type of culture, of course. Some are more water tolerant, meaning they tolerate higher water tables, while others prefer lower ones.

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Although everything may seem very good at first glance, the water table can also be a disadvantage. In the field of construction, it is essential to know this concept, and for good reason: If an excavation is carried out below the water table, the risk of subsidence and instability is much greater. So always keep that in mind.

When carrying out an excavation and/or a deep foundation, it is essential to know whether the water table will be reached or not. Steps can be taken from this wood to prevent groundwater from passing through and eventually seeping in. Physical barriers, pumping systems as well as combinations of the two methods mentioned above are normally used as containment measures. To choose the most appropriate measure, the depth of the excavation and the type of terrain must be taken into account.

Where is the water table located?

The water table is between the unsaturated zone and the saturated zone.

To get an idea of ​​where the water table is, we will list the different levels and rank them from top to bottom.

  1. Floor or surface: It is the most superficial layer and is part of the unsaturated zone.
  2. Ventilation area: It is also part of the unsaturated zone. Here, the pores found in the soil can hold both air and water. At this level is the hygroscopic water, which is that which adheres in a thin layer which surrounds the grains which are in the ground, and the capillary water. The latter is also found in the smallest pores. Moreover, it is responsible for causing capillary tensions in the saturated zone that touches the water table and is partially saturated above it.
  3. Hydrostatic level: It is a relatively thin layer, compared to the others, which separates the aeration zone from the saturated zone.
  4. Bangs : It is usually slightly higher than the water table. It basically separates the unsaturated zone from the saturated zone. This is where the groundwater is found, which saturates the pores located in the soil of the saturation zone. Next to this zone, the capillary fringe is generally tight.
  5. Saturated zone: It is composed of sediments and bedrock. In it, all the pores are filled with water. This water is usually in transit between the thickest cracks and pores and is called gravity water or gravitational water.

I hope I have clarified all your doubts about the water table, its usefulness and its location. As you can see, there is much more under our feet than dirt and insects. The Earth is full of mechanisms and strategies that help sustain living things.

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