- Intro – stating facts on groundwater decline.
- Briefly mention the consequences of declining groundwater table.
- Elaborate the reasons of urbanization-groundwater vicious link.
- Mention measures as way forward.
The groundwater level in 33% of the wells monitored by the Central Ground Water Board declined by 0-2 metres in 2020-2021, as compared to the decadal average. It also showed a decline of more than 4 metres in a few pockets of Delhi, Chennai, Indore, Vijayawada, Dehradun, Allahabad, Lucknow, etc., over the years. Like, Kolkata witnessed a decline in water table from 20 to 7 m since 2000; Ghaziabad has a drop to 12m; and Delhi has a drop of 0.5-2 m per year.
The awaited peril: India is the largest user of groundwater with 1/4th of the total global withdrawal. Indian cities cater to about 48% of its water supply from groundwater. The unmanaged groundwater and burgeoning population may result in seasonal water shortages by 2050 for an estimated 3.1 billion people, and perpetual water shortage for almost a billion. Further, water & food security will be compromised leading to more poverty despite developments.
Urbanization & groundwater – the vicious link: water supply, sanitation and drainage are key requirements of urbanization process. Groundwater being easily available near water-demand sites, it reduces the capital & operational costs, thus making it vulnerable to over-exploitation.
- The ever growing urban population increases demand for water as well as management of waste & polluted water.
- Unplanned urbanization has led to increase in built-up & paved area eliminating infiltration, reducing evapotranspiration and therefore, increases surface runoffs and urban flooding.
- Overexploitation of groundwater and increased number of private bore/tube wells to fulfill the demand-supply leads to deepening of water table, land subsidence, saline water intrusion and aquifer contamination.
- Transformation of natural landscape, watershed & flow direction often modifies groundwater cycle resulting in sharper decline or rise of groundwater levels accompanied by deteriorating quality. The subsoil strata becoming lose can result in hydraulic & corrosion effects on the building foundations.
- Urban groundwater is polluted by seepage contaminated with heavy metals, micro-pollutants, microbiological contamination through sewage system and on-site sanitation. Nitrate, Arsenic, Fluoride are some major elements responsible for groundwater pollution.
- Institutional vacuum is created as various organizations that manage groundwater lack accountability & responsibility. They are handicapped by limited knowledge and capacity. Also, there remains insufficient legal & regulatory mandate.
- For planning & management of groundwater, there needs to be focus on Integrated Water Resource Management Framework.
- Adopting water sensitive urban design and planning that can help maintain the water cycle by managing groundwater, surface water and rainwater for demand-supply.
- Taking a blue green infrastructure approach – green (trees, parks, gardens, etc.) and blue (wetlands, ponds, lakes, etc.) – while city/town planning. E.g. Bhopal’s green-blue smart city plan.
- Provision of waste water recycle to promote circular economy and sustainability.
- Interventions like rainwater harvesting, stormwater harvesting, rain garden, bio-retention ponds that intercept rainfall with vegetated lands are effective alternatives.
- Aquifer characterization & robust monitoring of urban groundwater quality and its data are imperative.
- Strengthening regulatory frameworks and stakeholder participation. Public awareness as well as trust building between formal water sector institutions and communities will fill the void in urban groundwater management.