WHAT IS THE PERCENTAGE OF FRESH WATER ON EARTH ?

WHAT WAS THE SOURCE OF WATER ON EARTH SURFACE?

The water was brought to the world’s oceans by the external sources thanks to icy comets, trans-Neptunian objects or water-rich meteoroids (protoplanets) from the outer reaches of the main asteroid belt(between Mars & Jupiter ) and these primitive meteorites which collided with the Earth helps to develop the source of water on the earth surface. but in fact, the exact time of the arrival of earth's water is still uncertain.

WHY WATER IS SO IMPORTANT RESOURCE? 

Water is often considered to be one of the most important resources our planet because we shouldn’t forget that a Human being can survive without for about several weeks, but without water, he would die in a matter of days.

       Water is a cyclic or renewable resources,¾ of the world is covered with water.

So what is the percentage of freshwater on earth?

In general, WATER makes up about 71% of the Earth’s surface, while the other 29% consists of continents and islands. To break the numbers down, 96.5% of all the Earth’s water is contained within the oceans as salt water, while the remaining 3.5% is freshwater lakes and frozen water locked up in glaciers and the polar ice caps.

Of that fresh water, almost all of it takes the form of ice: 69% of it, to be exact. If you could melt all that ice, and the Earth’s surface was perfectly smooth, the sea levels would rise to an altitude of 2.7 km.

so now let's move on to the next question ...

WHAT IS WATER RESOURCE?

• Water resources are sources of water that are potentially very useful. The uses of water include Agricultural, Industrial, Household, Recreational and Environmental activities. The majority of humans use requires Fresh water. and water provides the cheapest form of transportation too.

So, friends did you see how limited fresh water do we have in the earth? less than 3 %  but in the race of development, we are polluting & contaminating our water resources like anything. especially in the context of India, the situation of some rivers is more pathetic you can't even roam around the bank of this rivers due to very pungent smell & toxic water. example Yamuna river(Delhi).

Contamination of these fresh water resources leads to the problem of water scarcity...

WHAT IS WATER SCARCITY?

It is the lack of sufficient available water resources to meet water needs within a region.

WHAT ARE THE CAUSES OF WATER SCARCITY?

• over population
• pollution
• urbanization 
• power generation 
• excessive or misuse of water

• industrialization

To mitigate the problem of water scarcity the water harvesting practice is a very revolutionary & economical technique.but in the context of India is already being practiced in Ancient times. here is some example of the ancient hydraulic structure of India.

1-Water harvesting system: Sringaverapura 1st century BC.

2- Dams, Lakes: Chandragupta maurya

3-Irrigation works: Kalinga, Nagarjunakonda ,kolhapur.

4-Artificial lakes: Bhopal lake buit in 11th century

5-Tanks: Hauz khas (delhi built in 14 century )

 
RAIN WATER HARVESTING: 
Rain Water Harvesting is a very useful & environmental friendly utilization of rain water for domestic and agricultural uses it is already widely used In our country & throughout the world. It is a method which has been used since ancient times and is increasingly being accepted as a practical method of providing potable water even in a dry spell seasons throughout the world.


WHY THERE IS A NEED OF RAIN WATER HARVESTING?

—TO OVERCOME INADEQUACY OF SURFACE WATER TO MEET OUR DEMANDS

—TO REDUCE DECLINE IN GROUNDWATER  LEVELS

—SUSTAINABLE DEVELOPMENT

—TO IMPROVE GROUNDWATER QUALITY

—TO INCREASE AGRICULTURAL PRODUCTION

—TO ENHANCE ECOLOGY BY INCREASING VEGETATION COVER

—TO AVOID SURFACE RUNOFF

ADVANTAGES OF RAIN WATER HARVESTING 

—LOWER COST OF WATER STORAGE.

—EFFICIENT DISTRIBUTION SYSTEM.

—NO WASTAGE OF LAND.

—NO EXPOSURE TO EVAPORATION AND POLLUTION.

—ENVIRONMETALLY FRIENDLY.

—INCREASING PRODUCTIVITY OF AQUIFER.

—REDUCES FLOOD HAZARDS.

—INCRESING GROUND WATER LEVELS.

—MITIGATES EFFECTS OF DROUGHTS.

—REDUCES SOIL EROSION.

WHAT IS DAM?

A dam is a barrier across flowing water that obstructs, retards or channelize the flow of water and often creating an artificial reservoir.

CLASSIFICATION OF DAMS BASED ON STRUCTURE AND MATERIAL USED.

1-TIMBER DAMS

2-EMBANKMENT DAMS

3-MASONRY DAMS

WHAT ARE THE ADVANTAGES OF DAMS?

—FLOOD CONTROL

—HYDROELECTRICITY

—INLAND NAVIGATION

—RECREATIONAL FACILITIES

—WATER SUPPLY FOR DRINKING & INDUSTRIAL PURPOSES.

—IRRIGATION

—DEVELOPMENT OF PESCICULTURE

—CHECKING SOIL EROSION.

—PANDIT JAWAHAR LAL NEHRU PROCLAIMED THE DAMS AS THE “TEMPLES OF MODERN INDIA”

WHAT ARE THE DISADVANTAGES OF DAMS?

—SALINATION OF FARMLAND

—WATERBORNE DISEASES

—HIGH COST OF CONSTRUCTION

—POOR HABITAT FOR AQUATIC LIFE

—RESTRICTS NATURAL FLOW

—LOSS OF LAND AND BIODIVERSITY

—INCREASE EARTHQUAKE INTENSITY

—EXCESSIVE SEDIMENTATION

—SUBNERGING OF EXISTING VEGETATION.

SOME EXAMPLES OF DAMS (INDIA)

DAMS	RIVERS	STATES
SALAL D.P	CHENAB	J&K
Bhakra Nagal	Satluj	H.P & Punjab
Hirakund	Mahanadi	Odisha
Tungbhadra	Tungbadra	Andhra pradesh
Nagarjuna sagar	Krishna	Andhra Pradesh
Sardar Sarovar	Narmada	Gujarat
Naraura	Ganga	Uttar pradesh
Mettur	Kaveri	Tamil nadu
Panchet/konar/tilaiya	Damodar	jharkhand

how a water scarcity leads to the interstate water dispute? let's check it out?
Interstate water disputes arise when a river flows through two or more states & DAMMING at one state may affect the flow & volume in other states.
If the flow of the river is not well regulated that one state may be deprived multiple benefits of the river & other states may suffer leading to inter state disputes.

Some interstate water dispute India :

• Krishna-Godavari DISPUTES: Karnataka & Andhra Pradesh \•Kaveri water dispute: Karnataka & Tamil Nadu 

•Narmada river dispute: Rajasthan, M.P, Gujarat, Maharastra.

•Ravi-Beas water dispute: punjab & Haryana

sOME INTERNATIONAL WATER DISPUTES

Turkey-Iraq: Ilisu Dam and the Tigris River

Ethiopia-Egypt: Grand Ethiopian Renaissance Dam and the Nile River

China-India: The Brahmaputra River 

tWO MAIN ANDOLANS AGAINST OF DAMS

—NARMADA BACHAO ANDOLAN.

—TEHRI BACHAO ANDOLAN.

SOME IMPORTANT QUESTIONS

—HOW HAVE INTENSIVE INDUSTRIALIZATION AND URBANIZATION PASSED A GREAT PRESSURE ON EXISTING FRESHWATER RESOURCES IN INDIA? EXPLAIN WITH TWO EXAMPLES OF EACH.

—WHAT IS RAIN WATER HARVESTING? DESCRIBE THE PROCEDURE FOR ROOFTOP RAINWATER HARVESTING?

—COMPARE THE ADVANTAGES AND DISADVANTAGES OF MULTI- PURPOSE RIVER PROJECTS.

—WHAT IS WATER SCARCITY AND WHAT ARE ITS MAIN CAUSES?

—DESCRIBE ANY THREE HYDRAULIC STRUCTURE OF ANCIENT INDIA.

—EXPLAIN ANY THREE REASONS DUE TO WHICH LARGE DAMS HAVE COME UNDER GREAT OPPOSITION IN RECENT YEARS.

—WHAT ARE INTER-WATER DISPUTES? WHY ARE SUCH ISSUE RAISED? GIVE EXAMPLES OF INTER STATE WATER DISPUTES.

References: NCERT BOOKS, https://water.usgs.gov/edu/earthhowmuch.html 
                      https://en.wikipedia.org/wiki/Water_distribution_on_Earth