Water Scarcity, Management, and Conservation
- Water on Earth:
- 3/4th of the Earth’s surface is covered by water, but only a small fraction is freshwater suitable for use.
- Freshwater comes from surface runoff and groundwater, which are replenished through the hydrological cycle.
- Water is renewable because it moves through this cycle, but scarcity still exists due to factors like over-exploitation and unequal access.
- Water Scarcity:
- Even though water is abundant, many regions suffer from water scarcity. By 2025, nearly 2 billion people are expected to face water shortages.
- Water scarcity isn’t just about areas with low rainfall or drought-prone regions like Rajasthan; it can occur in areas with adequate water due to mismanagement and over-exploitation of water resources.
- Causes of Water Scarcity:
- Over-exploitation: In countries like India, excessive use of water for irrigation and industrial purposes has lowered water levels.
- Unequal access: Different social groups may have unequal access to water, causing scarcity in some areas.
- Growing population: Increased demand for water for domestic use, food production, and industries leads to depletion of resources.
- Pollution: Even if there is enough water, pollution from domestic waste, chemicals, and industrial activities can make it undrinkable.
- Agriculture’s Role: Irrigated farming is the largest consumer of water. Large-scale irrigation can deplete water supplies, affecting future agricultural productivity.
- Groundwater Depletion:
- Many farmers use wells and tube wells for irrigation, which can lead to falling groundwater levels, reducing water availability for future generations and affecting food security.
- Impact of Urbanization:
- Industrialization: Increasing number of industries use large amounts of water and electricity, often from hydroelectric power.
- Urbanization: Growing cities with dense populations place pressure on freshwater resources. Urban centers often rely on groundwater, which exacerbates the depletion problem.
- Need for Water Conservation and Management:
- Water management is crucial to avoid ecological crises, ensure food security, and protect ecosystems.
- Jal Jeevan Mission (JJM): The Indian government aims to provide safe and reliable water to rural households by installing piped water systems, ensuring 55 liters per person daily.
- Water Management and Traditional Systems:
- Ancient civilizations constructed hydraulic structures like dams, lakes, and canals to manage water. These methods still influence modern practices.
- Multi-purpose projects: Modern dams serve multiple functions like irrigation, hydroelectric power, water supply, and flood control. Examples include the Bhakra-Nangal project and the Hirakud project.
- Challenges with Large Dams:
- Environmental Impact: Dams can disrupt the natural flow of rivers, harm aquatic life, and lead to sedimentation (build-up of sediments) in reservoirs, which reduces their capacity.
- Flooding: Ironically, some dams, built to control floods, have worsened flooding due to sedimentation in reservoirs.
- Ecological Issues: Dams can cause soil salinization, land degradation, and loss of biodiversity due to changes in water use and flooding.
- Induced Earthquakes: Large dams can trigger small earthquakes due to changes in the water pressure in reservoirs.
- Water Conservation Methods:
- Modern initiatives like Atal Bhujal Yojana (Atal Jal) focus on water conservation in stressed areas, with an emphasis on community involvement.
- Changes in agricultural practices, such as using drought-resistant crops and water-efficient farming techniques, can also help conserve water.
- Suggestions for Water Conservation:
- Rainwater harvesting, recycling wastewater, efficient irrigation systems like drip irrigation, and reducing water wastage can significantly improve water conservation.
- Public awareness campaigns are essential to encourage people to change their attitudes towards water usage.
Key Takeaways:
- Water is renewable, but scarcity is caused by overuse, pollution, and mismanagement.
- The growing population, industrialization, and urbanization increase water demand.
- Water management through efficient use, pollution control, and traditional practices like rainwater harvesting can help conserve water.
- Dams have both benefits and drawbacks; while they provide irrigation and power, they can cause environmental issues.
- Governments are implementing programs like the Jal Jeevan Mission to provide clean water and ensure sustainability.
- Water Harvesting System:
- Ancient India had a strong tradition of water harvesting. People developed techniques based on local ecological conditions and rainfall patterns. These techniques were used to collect rainwater, groundwater, river water, and floodwater.
- Traditional Techniques:
- Guls/Kuls: In the Western Himalayas, these were diversion channels built for agricultural use.
- Rooftop Rainwater Harvesting: Commonly practiced in Rajasthan for storing drinking water. Water was collected from rooftops, filtered, and stored in underground tanks called ‘tankas’.
- Khadins and Johads: In Rajasthan, agricultural fields were converted into rain-fed storage structures to retain water and moisten the soil.
- Tankas in Semi-arid Regions: In Bikaner, Phalodi, and Barmer, underground tanks (tankas) were used to store drinking water. Some were large enough to store significant amounts of water, and water was collected after the first rain, which cleaned the roof and pipes.
- Modern Practices:
- Tamil Nadu is the first state in India to make rooftop rainwater harvesting mandatory for all houses, with legal provisions to punish defaulters.
- Shillong, Meghalaya: Despite receiving heavy rainfall (Cherapunjee and Mawsynram), Shillong faces water scarcity. Hence, nearly every house has a rainwater harvesting system.
- Gendathur, Karnataka: A remote village where 200 households use rooftop rainwater harvesting systems, collecting up to 100,000 litres of water annually. Gendathur receives about 1,000 mm of rainfall annually, and each household can harvest 50,000 litres.
- Challenges in Western Rajasthan:
- The practice of rooftop rainwater harvesting is declining due to the availability of water from the Indira Gandhi Canal, but some people continue to maintain tankas for better taste than tap water.
- Bamboo Drip Irrigation (Meghalaya):
- A 200-year-old system in Meghalaya uses bamboo pipes to tap stream and spring water. The water flows from hilltops to plant sites, where it is distributed drop by drop. This method allows efficient use of water for irrigation by reducing the flow to a small amount (20-80 drops per minute).
Key Concepts:
- Rooftop Rainwater Harvesting: Collecting rainwater from rooftops to store for drinking and other uses. This helps in areas facing water shortages, especially in urban areas like Shillong.
- Traditional Water Harvesting Systems: Systems like tankas, khadins, and johads were built to conserve water in arid and semi-arid regions, especially in Rajasthan.
- Bamboo Drip Irrigation: A sustainable method of irrigation that taps into natural springs using bamboo pipes, conserving water by applying it directly to plant roots.
Extra Knowledge for Competitive Exams:
- Water Crisis: India faces a major water crisis due to both scarcity and mismanagement. Rainwater harvesting is a critical solution to cope with water shortages, particularly in areas with low water table or erratic rainfall.
- Government Schemes: Schemes like the Jal Jeevan Mission (JJM) aim to provide piped drinking water to rural households. Such initiatives are linked to water conservation and management practices.
- Benefits of Water Harvesting: Helps in reducing dependence on groundwater, recharges aquifers, and improves the quality of water by reducing contamination.
THESE ALL ARE THE NOTES OF CHAPTER 3 GEOGRAPHY. AND AFTER SOME TIME YOU GET IMPORTANT QUESTIONS HERE. *#THANKS FOR VISITING, VISIT AGAIN#* 😊