Overview
This lecture covers the Class 10 Geography chapter on Water Resources, focusing on the importance, usage, scarcity, management, multipurpose projects, rainwater harvesting, and related challenges in India.
Introduction to Water Resources
- Water resources are essential for human, animal, and plant life, and support economic activities.
- Only a small fraction of Earth’s water is fresh and usable by humans; most is saline and found in oceans.
- Freshwater exists mainly as ice caps, glaciers, groundwater, and surface water (rivers, lakes).
Water Scarcity and Its Causes
- Water scarcity means insufficient accessible, potable water due to quantity or quality issues.
- Causes include uneven rainfall, increasing population, over-exploitation, unequal water access, pollution, industrialization, and urbanization.
- Water quality is also a concern, with contamination from fertilizers, pesticides, and industrial waste.
Need for Water Conservation and Management
- Water conservation ensures availability, health, food security, and ecological balance.
- Mismanagement and overuse lead to declining water tables and degraded resources.
- Water management methods include multipurpose projects and rainwater harvesting.
Multipurpose River Valley Projects
- Multipurpose projects (like dams) are constructed for irrigation, electricity generation, flood control, water supply, and recreation.
- Examples: Bhakra Nangal Project (Punjab), Hirakud Project (Odisha).
- These projects are referred to as “Temples of Modern India” due to their role in development.
Advantages and Disadvantages of Multipurpose Projects
- Advantages include irrigation, hydroelectricity, domestic/industrial water supply, flood control, and fish breeding.
- Disadvantages: displacement of people, loss of vegetation, changes in cropping patterns, inter-state water disputes, environmental concerns, and sedimentation.
- Sometimes fail in flood control due to excessive sediment buildup and sudden water release.
Rainwater Harvesting and Traditional Practices
- Rainwater harvesting collects and stores rainwater for future use, recharging groundwater and meeting local needs.
- Rooftop rainwater harvesting and traditional tanks (tanka system) common in Rajasthan.
- Other methods include diversion channels in hilly regions and bamboo drip irrigation in Meghalaya.
Conflicts and Movements
- Large dams often lead to displacement and environmental movements (e.g., Narmada Bachao Andolan).
- Inter-state disputes arise over river water sharing (e.g., Krishna, Cauvery rivers).
Key Terms & Definitions
- Water Scarcity — Lack of sufficient potable water in an area, due to either quantity or quality issues.
- Multipurpose Project — Large infrastructure (usually dams) serving multiple needs like irrigation, power, and flood control.
- Rainwater Harvesting — Collecting and storing rainwater for reuse, often for domestic, agricultural, or groundwater recharge purposes.
- Tanka System — Traditional underground tank for water storage, common in Rajasthan.
- Hydrological Cycle — The continuous movement of water through evaporation, condensation, precipitation, and runoff.
Action Items / Next Steps
- Read the NCERT chapter on Water Resources thoroughly.
- Revise all definitions, advantages/disadvantages of multipurpose projects, and rainwater harvesting methods.
- Prepare examples of major Indian multipurpose projects and traditional water harvesting systems.
- Attempt related textbook questions and be ready to explain water scarcity causes and solutions.