Wetlands act as natural sponges, yet their destruction converts a free ecological service into a costly public liability. Examine the role of wetlands in flood mitigation and groun

GS3 Environment & Bio-diversity
Wetlands act as natural sponges, yet their destruction converts a free ecological service into a costly public liability. Examine the role of wetlands in flood mitigation and groundwater recharge, and analyse the consequences of delayed legal protection with suitable examples

Examine

  • 15 marks
  • 8 min
  • 250 words
  • Hard

The Hindu

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Introduction

Wetlands are transitional ecosystems between terrestrial and aquatic environments that perform critical ecological functions. Recognising their importance, the Ramsar Convention defines wetlands as “biological super-systems.” In India, rapid urbanisation and encroachment have weakened their ecological role, transforming natural flood buffers into sources of disaster vulnerability.

According to ISRO’s National Wetland Atlas, India has nearly 4.6% of its geographical area under wetlands.

Role of Wetlands in Flood Mitigation

1. Natural Flood Buffers

  • Wetlands absorb and store excess rainwater like “natural sponges,” reducing flood peaks.
  • During intense rainfall, they slow surface runoff and moderate river discharge.

Example:

  • The East Kolkata Wetlands historically protected Kolkata from urban flooding by absorbing excess monsoon water.

2. Regulation of River Hydrology

  • Floodplain wetlands maintain hydrological balance by dispersing floodwaters across wider areas.
  • They reduce erosion and sediment load.

3. Coastal Protection

  • Mangrove wetlands act as barriers against cyclones and storm surges.

Example:

  • The Sundarbans mangroves reduced the impact of Cyclone Amphan.

Role in Groundwater Recharge

  • Wetlands facilitate percolation of water into aquifers.
  • They maintain base flow in rivers during dry seasons.
  • Inland wetlands support drinking water security and agriculture.

Example:

  • Wetlands around Hyderabad and Bengaluru earlier sustained local groundwater levels before large-scale urban encroachment.

1. Increased Urban Flooding

  • Encroachment and reclamation reduce water retention capacity.

Examples:

  • Chennai floods (2015): destruction of Pallikaranai marsh aggravated flooding.
  • Bengaluru floods (2022): loss of interconnected lakes and wetlands intensified inundation.

2. Groundwater Decline

  • Wetland degradation reduces aquifer recharge, worsening water scarcity.

3. Biodiversity Loss

  • Wetlands are habitats for migratory birds, fish and amphibians.
  • India has lost many urban wetlands due to delayed notification and weak enforcement.

4. Economic Burden

  • The loss of free ecosystem services leads to expensive investments in:

    • drainage systems,
    • flood control infrastructure,
    • water supply projects.

The Ramsar Secretariat estimates wetlands provide ecosystem services worth trillions of dollars globally.

  • Wetlands (Conservation and Management) Rules, 2017 excluded many smaller wetlands from strict protection.
  • Delay in identification and notification by States has weakened conservation efforts.

Example:

  • Maharashtra recently completed documentation of over 23,000 wetlands through NCSCM, highlighting earlier regulatory gaps.

Way Forward

  • Time-bound wetland mapping and legal notification.
  • Integration of wetlands into urban master plans.
  • Community-led conservation and stricter enforcement against encroachment.
  • Adoption of “sponge city” approaches for climate-resilient urbanisation.

Conclusion

Wetlands are ecological infrastructure essential for flood resilience, groundwater security and climate adaptation. Delayed legal protection converts these natural assets into public liabilities, increasing both ecological degradation and economic costs. Sustainable development requires treating wetlands not as wastelands, but as critical natural capital.