What is Groundwater: Sources, Pollution and Conservation

Groundwater refers to the freshwater that is found underground in the cracks and spaces in soil, rock, and sand. These waters are stored in and moves slowly through the geologic formations of soil, sand, and rocks known as aquifers. Groundwater accounts for about 95% of the nation’s freshwater resources. Here. we will study the topic in detail with some important questions. 

Groundwater

Water is the most vital source of existence necessary for the functioning of all forms of life on the planet earth. Groundwater is the water found beneath the surface in the fissures and voids of soil, sand, and rock. It is stored in aquifers, which are geologic formations of soil, sand, and rocks, and slowly moves through them. Groundwater is the purest form of water available on the earth with the very least amount of exposure to pollutants present in the atmosphere.

Groundwater contains little over 30% of the world's freshwater, whereas icecaps and glaciers contain roughly 68 percent. The surface water of lakes, rivers, and wetlands contains only approximately 0.3 percent of our freshwater.

Importance of Groundwater

• It is the primary supply of water for agriculture and the food processing industries.
• Groundwater is critical to the ecology because it maintains the water level and flows into rivers, lakes, and wetlands.
• Groundwater does not necessitate the construction of costly reservoirs to store water before it is used.

Different Types of Geological Formation of Groundwater

• Aquifer- An aquifer is a saturated earth formation. It not only preserves the water but also produces enough of it. Because aquifers are very permeable rocks, they are commonly used for groundwater applications. An aquifer is made up of unconsolidated sand and gravel deposits.

• Aquitard- A saturated formation is also known as an aquitard. It allows water to pass through it, although it does not yield as much water as an aquifer does. It's due to the fact that they're somewhat permeable. If an aquifer exists beneath the aquitard, however, the aquitard's water may leak into the aquifer. An aquitard is a sandy-looking clay kind. Clay particles fill in the sand's gaps, allowing it to be partially permeable.

• Aquiclude- An aquiclude is a geological feature that prevents water from flowing through it. Although it contains a big volume of water, it does not allow water to pass through it and does not yield water. Its high porosity is the reason for this. Aquiclude is a type of clay.

• Aquifuge- Aquifuges are impermeable geological formations that are neither porous nor permeable, meaning they can't hold water while also allowing water to pass through them. Aquifuge is a type of compact rock.

Porosity and Permeability

Porosity

It refers to a measure of the void spaces or pores that is present between particles of clay, grains of sand, or pieces of gravel, or in the layer. Generally, it is expressed as a fraction of the volume of void space divided by the total volume. It is written as a percentage between 0–100%.

Permeability

It is the most important variable in groundwater which describes how easily water can move between these pore spaces.

Ranges of Porosity and Permeability for Sediments

Groundwater Pollution

When pollutants are released to the earth and make their way down into groundwater, this is known as groundwater pollution. Within an aquifer, the pollution frequently generates a contaminated plume. The contaminant is dispersed over a larger area due to the movement of water and dispersion within the aquifer. Groundwater quality can be influenced by industrial discharges, urban activities, agriculture, groundwater pumping, and waste disposal. Human-caused contaminants include leaking gasoline tanks and dangerous chemical spills.

Groundwater Protection and Conservation Methods

1. Embrace your heritage.

Plants that are natural to our area should be used in your landscaping. They have a fantastic appearance and don't require much water or fertilizer. One should choose grass varieties that are suitable to our region's environment, since this will reduce the need for frequent watering and chemical applications.

2. Reduce the use of Chemicals

Reduce the number of chemicals you use in your house and yard, and make sure to properly dispose of them - Shouldn’t be dropped on the ground.

3. Waste Management

Dispose of potentially harmful materials such as unused chemicals, medications, paint, motor oil, and other materials properly. Household hazardous trash collections or sites are held in many towns; the local health department must be contacted in such cases.

4. Don't Let It Get Away

The water should be turned off when we brush our teeth or shave, and don't leave it running while we wait for it to cool down. 

5. Repair the Drip

Check for leaks in all of the home's faucets, fixtures, toilets, and taps and replace them right away, or install water-saving models.

6. Smarter Washing

We should try to practice a five-minute shower. Also, only run full loads of dishes and laundry in the dishwasher and washer.

7. Use Water Efficiently

Water the lawn and plants only when they are actually thirsty and during the coldest portions of the day. During dry periods, watering restrictions must be followed.

8. Reduce, Reuse, and Recycle

?Reduce, Reuse, and Recycle are three words that come to mind when thinking about the environment. Reduce the quantity of "things" we use and recycle as much as possible. Paper, plastic, cardboard, glass, aluminum, and other materials can all be recycled.

9. Alternatives Made from Nature

When feasible, use only natural/nontoxic household cleaners. Lemon juice, baking soda, and vinegar are all excellent cleaning agents that are both economical and environmentally friendly.

Groundwater Recharge

Water injected into the aquifer through the unsaturated zone after infiltration and percolation following any storm rainfall event is known as groundwater recharge. Groundwater levels are maintained, farmers' annual yields are enhanced, pumping expenses are lowered, and waterlogging is eliminated with this strategy. At a low cost, earthen irrigation systems can be converted into highly profitable regional groundwater recharge systems.

Methods of Groundwater Discharge

The volumetric flow rate of groundwater across an aquifer is known as groundwater discharge. This can be used to calculate the flow rate of water flowing over a plane with specified geometry, for example. It is done naturally by water cycle water from melting snow and rain seeps into the soil and travels down towards the saturated zone. Groundwater does not stay below the surface indefinitely, nor does it remain still. This water finally rises to the surface. This is referred to as discharge.

Recommended video:

Things to Remember based on Groundwater

• Groundwater is the purest form of water available on the planet earth.
• Groundwater is used for multiple purposes like irrigation, drinking, cleaning, and also used in industry and livestock.
• It is easier and cheaper to treat groundwater than surface water.
• An aquifer is a saturated earth formation.

• An aquiclude is a geological feature that prevents water from flowing through it. 
• Aquifuges are impermeable geological formations that are neither porous nor permeable.
• Groundwater pollution takes place when pollutants are released to the ground and make their way down in the groundwater. 
• Reduce the number of chemicals you use in your house and yard, and make sure to properly dispose of them to protect the groundwater. 

Sample Question based on Groundwater

Ques: What percentage of people rely on groundwater as a source of drinking water? (1 mark)

1. 70 percent.

2. 50 percent. 

100. 80 percent

500. 65 percent

Ans: Correct Answer a) 70 percent.

Ques: Which one has the most dissolved minerals? (1 mark)

1. Surface Water

2. Groundwater 

Ans: The correct answer is option b) Groundwater

Ques: In general, how far away does a well's source of groundwater come from? (1 mark)

1. A few miles or less.

2. 5 to 10 miles.

Ans: The correct answer is option a) A few miles or less.

Ques: What are the ways in which anyone can help in protecting groundwater? (1 mark)

1. Recycle used waste oil.

2. Dispose of hazardous and household chemicals properly.

100. Don't over-apply lawn chemicals.

500. All of the above. 

Ans: The correct answer is option d) all of the above.

Ques: When does groundwater have the greatest impact on the volume of water in a river or stream? (1 mark)

1. Spring.

2. Summer.

Ans: The correct answer is option b) Summer.

Ques: What is meant by porosity and permeability? (4 marks)

Ans: Porosity refers to a measure of the void spaces or pores that is present between particles of clay, grains of sand, or pieces of gravel, or in the layer. Generally, it is expressed as a fraction of the volume of void space divided by the total volume. It is written as a percentage between 0–100%.

Permeability is the most important variable in groundwater which describes how easily water can move between these pore spaces. 

Ques: State any four steps to conserve groundwater. (4 marks)

Ans: The steps to conserve groundwater are as follows:

• Embrace your heritage.

Plants that are natural to your area should be used in your landscaping. They have a fantastic appearance and don't require much water or fertilizer. Choose grass varieties that are suitable to your region's environment, since this will reduce the need for frequent watering and chemical applications.

• Reduce the use of Chemicals

Reduce the number of chemicals you use in your house and yard, and make sure to properly dispose of them - don't drop them on the ground!

• Waste Management

Dispose of potentially harmful materials such as unused chemicals, medications, paint, motor oil, and other materials properly. Household hazardous trash collections or sites are held in many towns; contact your local health department to find one near you.

• Use Water Efficiently

Water the lawn and plants only when they are actually thirsty and during the coldest portions of the day. During dry periods, make sure you, your family, and your neighbors follow any watering restrictions.

Ques: How is the groundwater polluted? (3 marks)

Ans: When pollutants are released to the earth and make their way down into groundwater, this is known as groundwater pollution. Within an aquifer, the pollution frequently generates a contaminated plume. The contaminant is dispersed over a larger area due to the movement of water and dispersion within the aquifer. Groundwater quality can be influenced by industrial discharges, urban activities, agriculture, groundwater pumping, and waste disposal. Human-caused contaminants include leaking gasoline tanks and dangerous chemical spills.

Ques: Why is groundwater a highly overused resource? (3 marks)

Ans: Groundwater is a highly overused resource for the reasons listed below:

1. This is due to the vast and increasing population which leads to the higher demand for and unequal access to water.
2. In order to increase irrigated lands, water supplies are being over-exploited and dry season cultivation to promote increased demand for food grains.
3. To fulfill water requirements in the rural areas, there exists a system of own groundwater pumping equipment in apartment complexes or communities.

Ques: What do you mean by groundwater recharge? (3 marks)

Ans: Water injected into the aquifer through the unsaturated zone after infiltration and percolation following any storm rainfall event is known as groundwater recharge. Groundwater levels are maintained, farmers' annual yields are enhanced, pumping expenses are lowered, and waterlogging is eliminated with this strategy. At a low cost, earthen irrigation systems can be converted into highly profitable regional groundwater recharge systems.

Previous Years’ Questions

Ques: How intensive industrialization and urbanization have posed a great impact on the existing freshwater resources in India? Explain with two examples for each. (2012)

Ans: Intensive industrialization and urbanization have a great impact on the existing freshwater resources. The demand for water has increased with the ever-growing number of industries:

• Industries highly use freshwater as water is required for cooling the machines as well as for the processing of goods.
• Also, the machines run on the power supplied by the hydel power plants.
• Around 22% of the total electricity is hydroelectric power.
• Rapid urbanization has also caused the expansion of industries which increased the requirement for water.
• The untreated industrial effluents which are discharged into water bodies are polluting the water bodies and making it hazardous for human consumption. This is also responsible for creating water scarcity.

On the other hand, the large urban populations and lifestyles have not only added to water and energy requirements but have further multiplied the problem by over-drawing the groundwater by using their own groundwater pumping devices in order to meet their water needs for domestic purposes such as cleaning, cooking, washing, etc.
Thus, water resources are being over-exploited leading to their depletion in several cities.

Ques: Write the adverse effects of over-exploitation of groundwater resources. (2015)

Ans: The effects of over-exploitation of groundwater are:

1. Pumping out more water from under the ground may result in depletion of groundwater levels.
2. It will adversely affect the availability of water.
3. This, in turn, will affect the agriculture and food security of the people.
4. Moreover, the impoverishment of water resources may adversely affect the ecological cycle as well.