Q 8. भारत में तटीय जलभृत में समुद्री जल घुसपैठ एक मुख्य चिंता का विषय है। समुद्री जल घुसपैठ के क्या कारण हैं तथा ऐसी आपदा का सामना करने के उपचारात्मक उपाय क्या हैं? (UPSC 2025,10 Marks,150 Words)

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Seawater intrusion in India's coastal aquifers poses a significant threat to freshwater resources, driven by over-extraction and rising sea levels. According to the Central Ground Water Board, excessive groundwater pumping disrupts the natural balance, allowing seawater to infiltrate. Rao et al. emphasize the need for sustainable water management and artificial recharge techniques to mitigate this issue. Implementing barrier wells and promoting rainwater harvesting are crucial remedial measures to combat this environmental hazard effectively.

Causes of Seawater Intrusion in Coastal Aquifers:
  ● Over-extraction of Groundwater:  
        ○ Excessive pumping of groundwater for agricultural, industrial, and domestic purposes reduces the freshwater pressure, allowing seawater to intrude into the aquifers.
        ○ Example: The coastal regions of Tamil Nadu and Gujarat have reported significant seawater intrusion due to over-extraction.
  ● Reduction in Natural Recharge:  
        ○ Urbanization and deforestation reduce the natural recharge of aquifers, leading to a decline in groundwater levels.
    ● Concrete surfaces in urban areas prevent rainwater from percolating into the ground.  
  ● Sea Level Rise:  
    ● Climate change contributes to rising sea levels, which increases the hydraulic pressure of seawater on coastal aquifers.  
        ○ Example: The Sundarbans region is particularly vulnerable to sea level rise.
  ● Land Subsidence:  
        ○ Excessive groundwater extraction can lead to land subsidence, further exacerbating seawater intrusion.
        ○ Example: Parts of Chennai have experienced land subsidence due to groundwater depletion.
 Remedial Measures to Combat Seawater Intrusion:
  ● Artificial Recharge of Aquifers:  
        ○ Implementing rainwater harvesting and constructing percolation ponds to enhance groundwater recharge.
        ○ Example: The Cherrapunji region has successfully implemented rainwater harvesting techniques.
  ● Regulation of Groundwater Extraction:  
        ○ Enforcing strict regulations on groundwater extraction, especially in critical areas.
        ○ Promoting the use of drip irrigation and other water-efficient technologies in agriculture.
  ● Construction of Subsurface Barriers:  
        ○ Building subsurface dams or barriers to prevent the movement of seawater into freshwater aquifers.
        ○ Example: Subsurface barriers have been used in Japan to control seawater intrusion.
  ● Afforestation and Vegetative Barriers:  
        ○ Planting mangroves and other salt-tolerant vegetation along coastlines to act as natural barriers against seawater intrusion.
        ○ Example: The Pichavaram Mangrove Forest in Tamil Nadu serves as a protective barrier.
  ● Desalination and Use of Alternative Water Sources:  
        ○ Investing in desalination plants to reduce dependency on groundwater.
        ○ Encouraging the use of recycled wastewater for non-potable purposes.
  ● Community Awareness and Participation:  
        ○ Educating local communities about the importance of sustainable water management practices.
        ○ Involving communities in water conservation and management initiatives.

Seawater intrusion in India's coastal aquifers is driven by over-extraction of groundwater, climate change, and rising sea levels. To combat this, strategies like artificial recharge, regulating groundwater extraction, and coastal afforestation are essential. According to the Central Ground Water Board, sustainable management is crucial. As Mahatma Gandhi emphasized, "Earth provides enough to satisfy every man's needs, but not every man's greed." A balanced approach ensures the protection of vital water resources for future generations.