Environmental Studies: Water Resources and Management

Environment and Natural Resources

Water Resources Overview

  • Distribution of Water Resources
    • Earth’s surface: 2/3 covered with water.
    • Total water: ~1400 million km³ (UNEP, 2002).
    • Oceans hold ~97.5% (saltwater), 2.5% is freshwater.
    • Breakdown of freshwater: 68.7% in glaciers, 30.1% in groundwater, 0.4% in lakes, rivers, wetlands, etc.

Global Water Resource Distribution

  • Countries with Major Freshwater Resources:
    • Canada, Indonesia, Brazil, Russia, U.S., Colombia, India, China, Peru = 60% of natural freshwater.
  • Countries Dependent on Water Resources:
    • 33 countries rely on external sources for over 50% of their renewable water.

Water Availability in India

  • Water Cycle in India: 4500 km³/year rainfall.
    • Storage in dams: 250 km³.
    • Surface water flow: 440 km³.
    • Aquifer storage: 432 km³.
    • Total freshwater availability: 1122 km³/year.
    • Utilizable surface water potential: 1869 km³/year, of which net usable for irrigation is 690 km³/year.

Sectoral Water Use in India

  • Overall Water Use:

    • Agriculture: 91% (688 km³/year)
    • Domestic: 7%
    • Industry: 2%

  • Comparison with Other Countries:

    • Water withdrawal per capita: India 621.4, China 409.9, Brazil 330.8, USA 1583.
    • India is the highest global user of water for agriculture.

Water Consumption Patterns

  • Urban Areas:
    • Highest demand in urbanized cities (e.g. Delhi, Mumbai)
    • 35-40% of urban water is lost due to leakages.

Industrial Sector Water Use

  • Industries: 15 km³/year for $113.041 Billion output.
    • Power generation: 2 km³/year for 855 billion units.

Water Management Initiatives

  • Wastewater Generation:

    • Produces 18 billion km³/year, with only 30% city sewage treated.
    • Untreated wastewater contaminates groundwater.

  • Recycling and Rainwater Harvesting: Plans to reuse treated wastewater could generate an additional 32 billion km³ annually.

Water Scarcity Conflicts

  • Examples of interstate water conflicts:
    • Middle East (Euphrates and Tigris rivers)
    • Indus water treaty between India and Pakistan.

The Narmada Issue

  • Narmada valley project consists of 30 major, 136 medium, and 3000 minor dams.
    • Controversies surrounding environmental impacts and rehabilitation for displaced persons.

Conclusion

  • Managing natural resources requires sustainable practices and addressing conflicts over water rights to ensure adequate resources for all sectors.