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Kolkata’s underground water crisis is becoming a serious issue, driven by rapid urbanization and the construction of high-rise buildings. The problem stems from excessive groundwater extraction, poor management, and challenges in urban planning. Below is an overview of the factors contributing to the crisis and potential sustainable solutions.

Key Factors Contributing to the Crisis:

Excessive Groundwater Extraction

Rising Demand:

Kolkata has witnessed a construction boom in recent years, with an increasing number of high-rise residential and commercial structures. These buildings rely heavily on groundwater for their water supply, especially in areas where municipal water is insufficient or unreliable. This has led to over-extraction of groundwater in many parts of the city.

Aquifer Depletion:

As a result, the water table in various areas, particularly the fast-developing peripheral zones, is falling rapidly. In some regions, groundwater levels have dropped by over 2 meters in recent years, creating a severe risk for the city’s water security.

Unregulated Bore Wells:

Many high-rise buildings depend on private bore wells to meet their water needs. These wells often operate without proper permits or oversight, extracting groundwater unchecked. The absence of an effective monitoring system exacerbates the problem, allowing illegal bore wells to deplete water resources without accountability.

Urbanization and Population Growth

Urban Development:

Kolkata’s population has been steadily growing, fueled by natural growth and migration from rural areas of West Bengal and neighboring states. This increase in population has intensified the demand for housing, leading to rapid construction of high-rise buildings, particularly in the city’s outskirts.

Loss of Permeable Land:

The expansion of urban areas and the spread of concrete structures have reduced the amount of permeable land, such as green spaces, ponds, and wetlands, which are essential for groundwater replenishment. As more land is covered with impermeable surfaces, rainfall is less able to seep into the ground, exacerbating the depletion of underground water reserves.

Water Demand Exceeding Supply:

Kolkata’s municipal water supply cannot meet the growing needs of its residents, prompting many to turn to private bore wells. In peripheral areas like New Town and Rajarhat, construction activities have intensified, further straining groundwater resources.

Public Negligence:

Even in areas with a satisfactory water supply, significant amounts of water are wasted due to public mismanagement. Examples include: Leaky Faucets and Pipes: Unnoticed leaks can waste large amounts of water over time. Excessive Water Use for Cleaning: Running water is often used for washing dishes, cars, or floors, when more efficient methods could reduce water wastage. Overwatering Plants: People may overwater gardens without considering the actual needs of the plants or weather conditions. Unnecessary Flushing: Excessive toilet flushing can waste clean water.

Lack of Low-Flow Fixtures: Traditional taps and showerheads consume more water than necessary compared to low-flow alternatives. Climate Change and Reduced Precipitation

Unpredictable Monsoons:

Climate change has disrupted monsoon patterns in West Bengal, leading to irregular and reduced rainfall. This decline in rainfall diminishes natural groundwater recharge, further straining the city’s water supply.

Rising Temperatures:

Kolkata, like many urban areas, experiences the “urban heat island” effect, where city temperatures are higher than those in surrounding rural areas due to human activities and extensive concrete surfaces. This increases water demand and accelerates the evaporation of surface water, leading to even greater dependence on groundwater.

Consequences of Groundwater Depletion:

Water Scarcity:

Groundwater depletion has led to significant water shortages, particularly in South Kolkata and peripheral areas like New Town and Rajarhat. Residents in these regions often rely on water tankers or private bore wells for their daily water needs.

Land Subsidence:

Excessive groundwater extraction can cause land subsidence—the gradual sinking of the ground. While Kolkata has not yet faced severe subsidence, continued groundwater depletion could lead to this issue, potentially damaging buildings, roads, and other infrastructure.

Saline Water Intrusion:

Kolkata’s proximity to the Bay of Bengal and the Sundarbans delta puts it at risk of saline water intrusion. Excessive groundwater extraction, especially in the southern parts of the city, can allow saltwater to infiltrate the aquifers, contaminating the groundwater and making it unsuitable for drinking or agriculture.

Health Risks:

As water shortages persist, many households and businesses are forced to use untreated or inadequately treated groundwater, which may contain harmful substances like arsenic and heavy metals. This poses serious health risks, particularly in areas where arsenic contamination is already a concern.

Solutions for Sustainable Groundwater Management:

Government Regulations and Monitoring:

The Kolkata Municipal Corporation (KMC) and local authorities enforce regulations on groundwater extraction, guided by the West Bengal Groundwater Resources Act of 2005, which mandates permits for bore wells. Stricter enforcement and real-time monitoring of groundwater levels in rapidly developing areas are crucial.

Rainwater Harvesting:

Rainwater harvesting systems are now required for new large-scale constructions, aimed at replenishing groundwater. However, enforcement is inconsistent, and a stronger push is needed to promote rainwater harvesting in both new and older buildings across Kolkata.

Promoting Sustainable Urban Development:

Protecting green spaces and wetlands, such as the East Kolkata Wetlands, is essential for enhancing groundwater recharge. Urban planning must prioritize sustainable practices, with strict zoning laws and improved infrastructure to reduce over-exploitation of groundwater.

Public Awareness:

Public awareness campaigns are critical to educating citizens about groundwater conservation and rainwater harvesting. Engaging local communities can encourage the adoption of sustainable water practices and foster a collective commitment to environmental stewardship.

Conclusion:

Kolkata’s groundwater crisis, driven by rapid urbanization and over-extraction, poses a significant threat to the city’s long-term water security. Addressing this issue requires coordinated efforts from the government, urban planners, and the public. Strict enforcement of regulations, widespread rainwater harvesting, and sustainable urban development practices are essential to conserve and replenish the city’s groundwater reserves. Without these measures, Kolkata may face a severe water crisis in the years to come, compounding the city’s existing environmental and infrastructure challenges.