Maharashtra Board Class 12 Environmental Education Chapter 5 Water Security PDF Download

5. Water Security

5.1 Water resources

5.2 Need and importance of water resources

5.3 Water scarcity

5.4 Water contamination

5.5 Water conservation and management methods

5.1 Water Resources

One of the major challenges we face is to provide safe drinking water and basic sanitation for all. At present, close to 1 billion people lack access to clean water sources and over 2.6 billion people lack access to basic sanitation. Nearly all of these people live in cities in developing countries.

Cities all over the world are facing a range of problems, from climate change and population growth, to deterioration of urban infrastructure. Cities of the future will have a hard time providing sufficient sanitation and efficiently managing with less reliable water. New approaches for urban water management will need to address these issues. New strategies to be developed to build resilient urban water systems. Rural settlements and cities in developing countries require to take special efforts for water management.

Do You Know?

United Nations World Water Day is held on 22nd March every year.

Events are organized on or around this day to increase the awareness about importance of water, environment, agriculture, health and trade in the society.

Activity 1

To observe World Water Day (WWD), you could organize meetings, discussion or an exhibition on water and its use. You can promote conservation of water in your school and your neighborhood.

Surface Water Sources

The major sources of fresh surface water are rivers, lakes, ponds and tanks. India is blessed with large number of major, medium and small size rivers. Rivers comprise the most important source of surface water. Ganga and Brahmaputra rivers have biggest catchment area in India.

In India due to topographical, hydrological and other constraints, only about 32 per cent of the available surface water can be utilized. You have studied in your 11th standard textbook, that precipitation in India has very high spatial variation and it is mainly concentrated in Monsoon season.

Groundwater Sources

Groundwater is a part of rainwater that percolates in the ground. Though ground water represents one of the most important water source in India, its availability depends on various factors viz topography, subsurface geology and prevailing climate.

The level of groundwater utilisation is relatively high in the river basins lying in north-western region and parts of south India. The groundwater utilisation is very high in the states of Punjab, Haryana, Rajasthan, and Tamil Nadu. However, there are states like Chhattisgarh, Odisha, Kerala, etc., which utilize only a small proportion of their groundwater potentials. States like Gujarat, Uttar Pradesh, Bihar, Tripura and Maharashtra are utilizing their ground water resources at a moderate rate.

If the present trend continues, the demands for water would need the proper water management systems to be implemented. The Central Ground Water Authority (CGWA) regulates the industrial ground water usage in the country.

Teacher's Note

India gets water from rivers, lakes, and underground sources. Many states in India use groundwater heavily, like Punjab and Rajasthan, because they have less rainfall.

Exam Trick

Remember: India has only 32% usable surface water. This is like having lots of money but can only spend a small amount. Most water runs away in monsoon rains.

Points to Remember

Surface water comes from rivers, lakes, ponds and tanks.
Groundwater is rainwater that goes deep into the soil.
Ganga and Brahmaputra rivers have the biggest catchment areas in India.
CGWA controls how industries use groundwater.
Only about 32% of surface water in India can actually be used.

5.2 Need and Importance

Although 71% of the earth is covered with water, acute shortage of water is reported all over the world. India receives nearly 4% of global precipitation, still it suffers from water scarcity. It is mostly caused by over exploitation, excessive use and uneven distribution of water. Pollution of water by domestic and industrial sources, seepage of chemicals are also responsible for water scarcity, as they make water hazardous for use.

Increasing industrialization is exerting pressure on existing water resources. Rapid urbanization has also increased the pressure on groundwater sources like tube wells. An important source of water, Indian rivers like Ganga, Yamuna etc. are polluted due to rapid industrialization, modern agricultural practices and urbanization.

Although water is a renewable resource, the misuse and wastage of water, has resulted in depletion of water resource. Conserving water has become a major environmental issue. In order to save and conserve it, we must reduce wastage of water. Reducing per capita consumption of water and preventing wastage are effective ways of water conservation.

Importance of Water

Water is an essential element and plays a key role in the human body. We can survive up to several weeks without food, but only a few days without water. Every system in the body, from cells and tissues, to vital organs requires water to function.

Do You Know?

Water carries nutrients to all cells in all organisms.

Water allows the body to absorb and assimilate minerals, vitamins, amino acids, glucose and other substances. Water flushes out toxins and waste.

Water helps to regulate body temperature.

Water makes up an average 60% of an adult's body weight and the body cannot store water. Every day we constantly lose water though breathing, sweating and through urine and faeces. Ensuring that lost fluids are replenished in a timely manner is essential for good health.

Activity 2

Class teachers should organise a discussion on reuse and recycle of water.

Teacher's Note

Water is very important for our body. Think of water like fuel for a car - without fuel, the car cannot run, and without water, our body cannot work.

Exam Trick

Remember: We are 60% water. We can live weeks without food but only days without water. This shows how important water is for life.

Points to Remember

Water is needed by every part of our body to work well.
Water carries food nutrients to all our cells.
Water helps cool our body and remove waste.
Our body is 60% water.
We lose water every day by sweating, breathing and other ways.

5.3 Water Scarcity

Water is vital requirement of life. By 2025 more than 50 countries including India will face water scarcity problem.

Water is available through uneven monsoon rains in India. Average rainfall is 117 cm in India and 101 cm in Maharashtra. Availability of water is more than 300 cm in Konkan while very less i.e. 50 cm in eastern parts of districts like Sangli, Satara, Solapur, Marathwada districts etc. There is highest rainfall is Amboli and Gadchiroli in monsoon but there is scarcity of water in summer. The surface run-off is more due to slope of mountains and non-availability of storage.

Teacher's Note

Some parts of India get lots of rain while other parts get very little rain. This is like some children getting many toys while others get none - it is not fair.

Exam Trick

Remember: By 2025, more than 50 countries including India will have water shortage. Monsoon rains are not even - some areas get too much, others get too little.

Points to Remember

By 2025, over 50 countries will face water scarcity problem.
India's rainfall is not equally spread - some areas get 300 cm while others get only 50 cm.
Even when it rains a lot, water runs away quickly on slopes and is not stored.
Summer season has water shortage even in areas with heavy monsoon rains.
Water scarcity is a growing challenge for India.

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