10. What are the environmental implications of the reclamation of the water bodies into urban land use? Explain with examples.

Introduction

The rapid expansion of urban areas has led to the large-scale reclamation of water bodies such as lakes, wetlands, and riverbeds to accommodate infrastructure. While this supports immediate developmental goals, it has long-term adverse environmental implications.

Environmental Implications

Disruption of Ecosystems: Wetlands, lakes, and rivers often support diverse flora and fauna that are adapted to specific hydrological conditions. Reclaiming water bodies for urban development can lead to the disruption of delicate aquatic ecosystems.

Urban Flooding: Reclaimed water bodies can no longer absorb rainwater, leading to waterlogging and flash floods.

Groundwater Depletion: Wetlands and lakes recharge groundwater; their loss reduces infiltration and lowers the water table.

Water Pollution: Water bodies naturally have to ability buffering out contaminants. Their encroachment disrupts this function, leading to the accumulation of toxic elements like arsenic, copper, and chromium in the groundwater.

Urban Heat Island Effect: Water bodies help regulate microclimates by absorbing heat and maintaining moisture. When replaced by concrete and asphalt, they intensify the Urban Heat Island effect—where urban areas become significantly hotter than their rural surroundings—leading to more frequent and severe heatwaves.

Impact on carbon sequestration: The reclamation of water bodies for urban use contributes to climate change by reducing the ability of natural ecosystems to sequester carbon. Wetlands, for example, are effective carbon sinks, and their destruction during reclamation releases stored carbon into the atmosphere

Disruption of Natural Drainage Systems: Altering water bodies disturbs the natural hydrology, affecting river flow and increasing erosion risks.

Coastal Regions : Water reclamation in coastal areas is a major driver of wetland loss and degradation. It also aggravates earthquake impacts by increasing the risks of soil liquefaction and land subsidence.

Example:

Bengaluru’s vanishing lakes have contributed to the city's declining groundwater levels.

Delhi's Yamuna floodplains are 75% encroached, threatening the river's ecology and the city's groundwater recharge.

One of the reasons Guwahati’s recurring flash floods are also  due to the encroachment of its natural drains and wetlands. Rapid urbanisation has choked rivers and beels, reducing the city’s capacity to absorb rainwater.

The East Kolkata Wetlands absorb a significant amount of carbon from wastewater, preventing it from entering the atmosphere. However, ongoing encroachment threatens this natural carbon sink, undermining its role in climate regulation.

The shrinking East Kolkata Wetlands has impacted migratory bird populations and local fisheries.

Conclusion

Reclamation of water bodies for urban use leads to severe ecological loss. Protecting them is essential for climate resilience and sustainable urban growth.