Introduction

Water is a vital natural resource essential for life, agriculture, and industrial growth. India faces significant challenges in managing its water resources due to unequal distribution, overuse, and pollution. This chapter provides an in-depth understanding of the importance, distribution, challenges, and conservation methods related to water resources in the country.

Importance of Water

• All living organisms need water for survival.
• Human bodies are composed of about 60-70% water.

• Agriculture accounts for the largest water consumption in India.
• Irrigation supports crops in regions with insufficient rainfall.

• Water is crucial for manufacturing, processing, and cooling in industries.
• Power plants also require water for generating electricity.

• Drinking, cooking, cleaning, and other household activities depend on water.

Water Distribution in India

• India receives 4,000 billion cubic meters of annual precipitation, but only about 1,122 billion cubic meters is available for use due to evaporation and seepage losses.
• Surface Water Sources:
  • Includes rivers, lakes, and reservoirs.
  • Unevenly distributed across regions.
• Groundwater Sources:
  • Found below the Earth’s surface in aquifers, extracted through wells and boreholes.

• Abundant Water Resources:
  • Regions like the Ganga-Brahmaputra basin receive high rainfall.
• Scarce Water Resources:
  • Arid and semi-arid regions like Rajasthan and parts of Gujarat face acute water shortages.

Challenges of Water Resources

• Resulting from overuse, unequal distribution, and wastage.
• Overdependence on monsoons exacerbates the problem.

• Domestic, industrial, and agricultural waste contaminates rivers, lakes, and groundwater.

• Excessive withdrawal for irrigation and industrial use reduces groundwater levels.

• Alters rainfall patterns and causes erratic monsoons, leading to water scarcity.

Multipurpose River Valley Projects

Projects designed for multiple objectives like irrigation, hydroelectric power generation, flood control, and water supply.

1. Bhakra Nangal Dam (Sutlej River): Provides irrigation, generates power, and controls floods.
2. Hirakud Dam (Mahanadi River): One of the longest dams in the world.
3. Damodar Valley Project (Damodar River): Modeled after the Tennessee Valley Authority in the USA.

• Provide irrigation to large areas.
• Generate hydroelectric power, reducing dependence on fossil fuels.
• Control floods in river basins.

• Submerge large areas, causing displacement of people.
• Lead to environmental degradation and loss of biodiversity.
• Increase sedimentation in reservoirs, reducing their capacity over time.

Water Conservation

1. Khadins and Johads: Traditional water harvesting systems in Rajasthan.
2. Rooftop Rainwater Harvesting: Collecting rainwater from rooftops for storage and future use.

1. Rainwater Harvesting: Collecting and storing rainwater to recharge groundwater or for direct use.
2. Watershed Management: Conserving water resources in a specific area by controlling surface runoff.
3. Efficient Irrigation Techniques:
   • Drip Irrigation: Supplies water directly to the roots of plants.
   • Sprinkler Irrigation: Distributes water evenly across fields, reducing wastage.

Rainwater Harvesting in India

• Rajasthan: Johads and Khadins.
• Maharashtra: Bandharas and Tals.
• Tamil Nadu: Eris (tanks).

• Recharge pits and underground storage tanks to collect rainwater.

Soil and Water Conservation Measures

1. Contour Ploughing: Ploughing along the contours of a slope to reduce soil erosion.
2. Terrace Farming: Creating terraces on slopes to slow water runoff and prevent soil erosion.
3. Strip Cropping: Growing crops in alternate strips to prevent wind and water erosion.
4. Shelter Belts: Planting trees along agricultural fields to reduce wind speed and soil erosion.

Key Definitions

1. Surface Water: Water available on the Earth’s surface in rivers, lakes, and reservoirs.
2. Groundwater: Water stored in underground aquifers, extracted through wells.
3. Rainwater Harvesting: Collection and storage of rainwater for future use.
4. Watershed Management: Conservation and management of water resources in a particular area.
5. Multipurpose Projects: Projects serving multiple purposes, such as irrigation, power generation, and flood control.

Key Statistics

• India has 2.4% of the world’s land area but 4% of global water resources.
• Per capita availability of water in India:
  • 5,177 cubic meters (1951)
  • 1,545 cubic meters (2011)

Importance of Water Conservation

1. Ensures sustainable development for future generations.
2. Prevents desertification and maintains ecological balance.
3. Supports agriculture and food security.
4. Mitigates the impacts of climate change and water scarcity.