water resources

• The United Nations has recognized access to water as a basic human right, stating that water is a social and cultural good, not merely an economic commodity
• Water has been harvested in India since the dawn of civilization
• The Ramayana, Mahabharata, and various other Vedic, Buddhist, and Jain texts contain several references to water harvesting structures in existence and water being revered as a life-giving and sustaining force
• Water covers 70% -75% of the earth's surface


  97.2% is locked in sea or oceans (1332 million cu. km, considering total availability as 1400 million cu km), 3% is fresh water 2.15% in polar ice caps (29.20 cu. km), < 1% available as surface and sub-surface water (rivers, streams, lakes)
• Water is a renewable resource. It may change its form but the quantity of water on Earth has remained the same for millions of years
• Out of 1400 million cu. km. of water available on earth, only 14 million cu. km. is fresh water
• As per the National Commission on Agriculture, considering an average rainfall of 1200mm, the water wealth of India is about 400 million hectares meters
• Main sources of water for our use

  • Rainfall
  • Groundwater
  • Surface water
• Rainfall in India


  • India can be broadly divided into 15 ecological regions
  • With an average annual rainfall of 1170 mm, India is one of the wettest countries in the world
  • There are large variations in the seasonal and geographical distribution of rainfall over the country
  • Nearly three-quarters of the rain pours down in less than 120 days, from June to September
• Groundwater in India


  • India's groundwater resources are almost ten times its annual rainfall
  • The country has an annual exploitable groundwater potential of 26.5 million hectares
  • Nearly 85% of currently exploited groundwater is used only for irrigation
  • Groundwater accounts for as much as 70-80% of the value of farm produce attributable to irrigation
  • Groundwater is now the source of four-fifths of the domestic water supply in rural areas, and around half that of urban and industrial areas
  • The water table almost everywhere in India falls between one to three meters every year
  • India is using its underground water resources at least twice as fast as they are being replenished
  • Excessive groundwater mining has caused land subsidence in several regions of Central Uttar Pradesh
• Surface water in India

  • There are 14 major, 44 medium, and 55 minor river basins in the country
  • The major river basins constitute about 83-84% of the total drainage area
  • This, along with the medium river basins, accounts for 91% of the country's total drainage
  • India has the largest irrigation infrastructure in the world, but the irrigation efficiencies are low, at around 35%
• Today, due to increasing consumption patterns, water is becoming scarce and this scarcity is an emerging threat to the global population, rendering the adages of the Bible and Koran irrelevant
• Global consumption of water is doubling every 20 years, more than twice the rate of human population growth
• At present more than one billion people on earth lack access to fresh drinking water
• By the year 2025, the demand for freshwater is expected to rise to 56% above what currently available water can deliver if current trends persist
• Water stress


  • A region where renewable fresh water availability is below 1700 cubic meters/capita/annum
  • A region where availability falls below 1000 cubic meters/capita/annum experiences chronic 'water scarcity'
  • If it falls below 500 cu.m. it is the state of "Absolute Scarcity"
• The annual per capita availability of renewable freshwater in India has fallen from around 5,277 cubic meters in 1955 to 2,464 cubic meters in 1990
• Given the projected increase in population by the year 2025, the per capita availability in India is likely to drop to below 1,000 cubic meters i.e., to levels of water scarcity
• India is expected to face critical levels of water stress by 2025
• At the global level, 31 countries are already short of water, and by 2025 there will be 48 countries facing serious water shortages
• The United Nations has estimated that by the year 2050, 4 billion people will be seriously affected by water shortages
• This will lead to multiple conflicts between countries over the sharing of water
• Around 20 major cities in India face chronic or interrupted water shortages
• There are 100 countries that share the waters of 13 large rivers and lakes
• The upstream countries could starve the downstream nations leading to politically unstable areas across the world
• Examples are Ethiopia, which is upstream of the Nile, and Egypt, which is downstream and highly dependent on the Nile
• International accords that will look at a fair distribution of water in such areas will become critical to world peace
• Uses of water


  • Agricultural
  • Industrial
  • Household
  • Recreational
  • Environmental
• No plant or animal species can survive without water
• If water in our body drops by 1% we feel thirsty, if it drops by 10% we face death
• Reasons for decline of groundwater

  • Population explosion
  • Overutilization of Surface and Groundwater
  • Deforestation
  • Hydropower generation
  • Dams - for Agriculture and Power Generation
  • Erratic and inadequate rainfall
• The world population is > 6 billion and will continue to increase significantly during the next few decades
• The total annual freshwater withdrawals today are estimated at 3800 cubic kilometers, twice as much as just 50 years ago
• Once hill slopes are denuded of forest cover, the rainwater rushes down the rivers and is lost
• Forest cover permits water to be held in the area permitting it to seep into the ground, charging the underground stores of water in natural aquifers
• The destruction of forests influences the regulation of the natural water cycle
• The removal of dense and uniform cover over the hilly zones leads to the occurrence of floods in drainage basins
• A large amount of water is used for generating power which is otherwise used for human needs
• India's increasing demand for water for intensive irrigated agriculture, for generating electricity, and for consumption in urban and industrial centers, has been met by creating large dams
• Dams support 30 to 40% of this area