Karnataka is one among the most drought-prone states in India, with 16 of the 24 most drought-prone districts. The vulnerability of the state has increased significantly in recent years, with 156 taluks, declared drought-hit in 2018-19. Reports from KSNDMC (2017)  indicate a rise in the frequency and severity of drought-affected areas, underscoring the urgency of water management interventions.

Among them, Kolar, Chikkaballapur, Bengaluru rural and Anekal (part of the Eastern Dry Agroclimatic Zone) are classified as permanently drought-prone, highlighting the region’s chronic water scarcity.

This region experiences low and erratic rainfall (often below 750 mm annually), high evaporation rates, and heavy groundwater depletion. Groundwater, once the lifeline of these areas, is now heavily depleted, with borewell depths exceeding 1,000 feet, making extraction costly and unreliable. The decline of traditional tanks, erratic rainfall (often below 750 mm annually), and high evaporation rates have further exacerbated the crisis. Meanwhile, rapid peri-urban expansion has intensified water demand, forcing residents to rely on expensive private tankers and RO vending machines, paying INR 5 per 20 litres for drinking water.

In this context, shallow aquifers present a critical opportunity for water resilience. Historically, India’s water heritage—from the Kuls and Step Wells of the West to the Kalyanis and Pushkaranis of the South—was deeply rooted in managing and sustaining shallow groundwater sources. These systems, maintained by communities and skilled well-diggers like the Mannu and Kallu Vaddars, ensured decentralised and sustainable water access. However, as cities urbanise, open wells have fallen into disrepair, buried under waste or lost to real estate pressures.

As part of the Shallow Aquifer Management (SAM) initiative under AMRUT 2.0, Biome Environmental Trust, in collaboration with IISc, is spearheading research-backed interventions supported by a ₹3 crore DST grant. This initiative not only addresses immediate water shortages but also lays the groundwork for sustainable urban water management, ensuring long-term resilience against climate-induced water stress in semi-arid regions.

Biome Environmental Trust has been working to reverse this trend by integrating shallow aquifers into urban water management. This proposal builds on Biome Environmental Trust’s Integrated Urban Water Management approach in Devanahalli, Karnataka, where treated wastewater from Bengaluru and rainwater recharge a shallow aquifer (via a lake) meets 12% of water needs for 40,000 people (as of Dec 2024). Revived open wells and shallow filter borewells supply water treated to BIS-10500 standards, demonstrating local reuse’s viability and community and local government acceptance.  This is India’s first initiative incorporating shallow aquifers into formal water supply systems using Soil Aquifer Treatment (SAT), a model that could be expanded to meet full water demand while reducing reliance on deep borewells and high-energy extraction.

Fig 1. Integrating shallow aquifers for urban water supply in Devanahalli town 

Fig 2. Activities under Devanahalli “Living Lab” 

Given the growing impacts of climate change and worsening drought conditions, restoring shallow aquifers is not just a conservation effort—it is a strategic necessity. An open well, full of safe water, is a sign of a well-managed city, offering the lowest economic cost, the least carbon emissions, and a tenth of the energy required for deep borewell extraction. By reclaiming open wells and digging recharge structures, we can create a decentralised, climate-resilient water strategy, ensuring long-term urban and rural water security. 

To enhance water resilience, the initiative aims to treat and reuse wastewater to recharge shallow aquifers, restore traditional water sources like open wells and filter borewells, and integrate them into municipal supply systems.