Water Table

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Water is an essential component of the earth. Whether it is living beings or non-living beings, everybody needs water. Water on earth is present in various forms such as jet streams, oceans, lakes, glaciers and is then stored in the form of groundwater. The water table is basically an underground boundary that is present in between the soil surface and the spaces where groundwater saturates. At this boundary the water pressure and the ground pressure are equal. Underneath this water, the table is a zone known as the saturated zone where water fills all spaces between the sediments. 

What is a Water Table? 

As we read above, it is an underground boundary that is present between the soil surfaces and the area where the groundwater saturates. The unsaturated zone is the area of the soil surface that is present above the water table. It is a space where oxygen and water fill the area between the sediments. Another name for an unsaturated zone is the zone of aeration. Underneath this water table, there is a saturated zone where water fills spaces between the sediments. 

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Water Tables around Us

Water tables are present almost everywhere in the world but the amount of water in these tables vary. The levels of water tables can also drop significantly if the water is not extracted in a well-sustained manner. This non-sustainable practice has shown that the large reservoirs of water are being depleted around the world. The largest affected areas are India, the USA, China where they are almost depleted to a point where they can’t be restored. 

Shape and Height of Water Table

It is basically influenced by the land surface that lies above a water table. When it curves under hills it is called a tall water table and when it drops under valleys it is called the small water table. The source of the water table is precipitation. When a water table naturally meets the land surface then it makes springs. 

Variations in the Water Table 

The levels of the water table can vary in different areas and even within the same areas. These are basically caused by the changes in precipitation between the seasons and years. In winter and spring season it is cold conditions outside so the level of water is high and hence the level of water table rises which makes them best water table. However, there is a gap when the saturated zone is infiltrated by precipitation. The reason being that water takes time to trickle through the spaces that are present in the sediments to reach out to the saturated zone. The process of irrigation is also helpful in raising the water table as excess water reaches the ground. But during the summer months when the temperature is hot and humid outside the levels of the water table depletes. Also at this time, the plants take up more water from the ground and a lot of water is wasted in the process of transpiration. We, humans, are also responsible for lowering levels of the water table by our practice of extracting the groundwater and not using it efficiently. The levels of depth of water table can be measured which are further used in determining the effects of season, climates, or human impact on groundwater. 

Uses of the Water Table

As we studied in the above paragraphs that water is an essential part of every living being on this earth therefore a water table also holds good importance and is very useful. Some of the uses are listed below. 

  • Water tables are useful for measuring aquifers that are saturated areas beneath the water table. These aquifers are used to extract the water for plants and human beings. 

  • The water from the water table can be used for bathing and cleaning purposes. 

  • It is used to water plants as in this way some water goes back to the ground and can be used again and again. 

  • But more and more extraction of this water on daily purposes is causing the water tables to deplete. 

  • This depletion of water is also known as aquifer depletion. 

  • Basically, the water from water tables finds its most uses in irrigation, drinking, industries, and hygiene. 

  • People of the particular areas where they have a good amount of water in their water table often put them on sale which is known as water table sale.

FAQ (Frequently Asked Questions)

1. Which is one of the biggest aquifers in the world.

Answer: The Oglala aquifer which is present in North America is one of the biggest aquifers in the world. It stretches for more than 450,000 square kilometers of the area which is distributed through the parts of New Mexico, Texas, South Dakota, Nebraska, Wyoming, Oklahoma. More than 3000 cubic kilometers of groundwater is present in it. 

2. What are the main reasons that the amount of water in water tables has decreased?

Answer: The amount of water in a water table is mainly governed by the ground cover of that area. Areas that are spongy and have absorbent vegetation have more amount of water in the water table as the water is easily absorbed by the ground. In urban areas, everything is covered with solid pavements whether its parking slots or ground we have a hard covering of marbles which makes it difficult for water to reach the water table, and hence their levels have decreased.