science

Water extraction

Water extraction is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Water extraction rather than just read about it. In short: Water extraction (also known as water withdrawal, water abstraction, and water intake) is the process of taking water from any source, either temporarily or permanently, for flood control or to obtain water for purposes such as irrigation. The extracted water could also be used as drinking water after suitable treatment.

Key takeaways

Water extraction belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Water extraction to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Water extraction from memory before moving on to harder problems.

Reference excerpt

Water extraction (also known as water withdrawal, water abstraction, and water intake) is the process of taking water from any source, either temporarily or permanently, for flood control or to obtain water for purposes such as irrigation. The extracted water could also be used as drinking water after suitable treatment. Depending on the environmental legislation in the country, controls may be placed on extraction to limit the amount of water that can be removed. The over-extraction of water can lead to dry rivers or declining groundwater levels. The science of hydrogeology is used to determine safe water extraction levels. Water can go through dams that are used to regulate or stop water from coming though, creating hydroelectricity.

Effects of overextraction

Saltwater intrusion

Groundwater contamination Groundwater contamination of water is seen vastly through the high needs of irrigation, drinking, and to support organic life. Keeping contaminants at a minimum is at a high demand and treated using arsenic, chloride and other chemicals to extract the pollutants. Humans can be a direct cause of these pollutants through over-extraction. Certain leading causes for groundwater contamination comes from lowering water tables due to the over-extraction of water and the water table not being able to recharge as quickly as needed. With this being said, polluted water from the surface (rivers and streams), makes its way into the groundwater more quickly and easily and results in a water quality problem due to the surface water pollution. Mining, farming and industrial activities contribute to water pollution, in particular where "countries lacking adequate regulation or controls".

Land subsidence Land subsidence is another effect linked to the over-extraction of groundwater. When large amounts of groundwater is extracted from aquifers beneath, surrounding areas above. When water from the aquifer is extracted at a large amount, the sediment, certain rock types, is separated due to the lack of water being used to make sure the sediment stays tightly together. The over-extraction of groundwater is a human caused activity that causes these ground failures that create pore spaces where water once was occupying. The sudden sinking of the soils surface causes infrastructure damage and a higher risk of flood damage due to the displacement of the Earth's surface.

Groundwater extraction laws Groundwater laws detail rights relating to water extraction and water withdrawal from aquifers.

United Kingdom In England, anyone wishing to withdraw more than 20 cubic metres of water per day, either from a river or an aquifer, must first obtain an abstraction licence from the Environment Agency. The licensing regime was introduced in the 1960s and by the time the government's White Paper on Water was put forward in 2011, it had been recognised that the rules were no longer fit for purpose.

United States

In the United States, much of the groundwater that is mainly withdrawn or extracted from aquifers consist of primarily irrigation towards the southwest and the west, with close to 85 to 90% of available water withdrawn. With an expected increase of the demand of water for domestic usage in the future, systems are to be regulated and land rights vary on the consumption of groundwater rights. When requirements have not been met through the water extraction, states control water resources and take steps on authorization of the requirements for groups of individuals or corporations.

See also Atmospheric water generator Desalination Reclaimed water Groundwater extraction

References

Further reading Infinite Water Holdings Limited. (n.d.). Groundwater Contamination & Treatment Solutions. Infinite Water. https://www.infinitewater.com/articles/groundwater-contamination-treatment-solutions Water School Science. (n.d.). Land subsidence completed. Land Subsidence | U.S. Geological Survey. https://www.usgs.gov/special-topics/water-science-school/science/land-subsidence

Illustrations

Worked examples

Example 1 — a first encounter with Water extraction

Start with the simplest possible case. Write down what Water extraction claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Water extraction before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Water extraction ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Water extraction

In research: Water extraction appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Water extraction in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Water extraction is common in secondary-school and first-year university syllabi. It links to neighbouring topics Hydrology, Water management, so understanding it makes those chapters shorter.
In everyday life: Look for Water extraction outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Water extraction in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Water extraction means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Water extraction out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Water extraction in simple terms?

Why does Water extraction matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Water extraction?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Water extraction.