In a pioneering move that addresses Guwahati's severe water challenges, the Assam Electricity Regulatory Commission (AERC) has implemented an innovative and affordable rainwater harvesting system that serves as a blueprint for sustainable water management in the city.
From Dry Borewells to Water Sustainability
The project emerged from necessity when the commission's 830-foot deep borewell, installed in 2016, went completely dry during February-March last year. This forced the office to depend entirely on expensive private water suppliers. Ashok Kumar Barman, AERC secretary who led the initiative, revealed they were spending over Rs 33,000 every month to purchase approximately 72,000 litres of water for their office operations.
Faced with this crisis, the commission considered drilling a new, deeper borewell at an estimated cost of Rs 25 lakh. Instead, they opted for a more sustainable and cost-effective solution: a comprehensive rainwater harvesting system that cost merely Rs 17,000 to install, complemented by a new 226-foot borewell costing about Rs 2.5 lakh that would be sustained through groundwater recharge.
How the Revolutionary System Works
The innovative setup captures rainwater from the building's 10,000 square foot rooftop, channeling it through an organized network of pipes and gutters. The system incorporates sophisticated filtration mechanisms including a first-flush device that diverts initial runoff carrying dust and debris, followed by sedimentation chambers and additional filters that further purify the collected water.
The treated water then percolates into the ground through specially designed recharge units, effectively restoring the depleted groundwater levels. This system captures approximately 3,280 cubic feet or about 24,534 gallons of water from rooftop rainfall. Barman expects the recharged groundwater to sufficiently meet the office's water requirements throughout the dry season until the monsoon returns in April-May.
Broader Implications for Guwahati's Water Future
This initiative arrives at a critical juncture for Guwahati, where groundwater depletion has reached a 'semi-critical' stage since 2022 according to official reports. The Central Ground Water Board (CGWB) has documented alarming declines in extractable groundwater resources across Assam, with Guwahati experiencing the most severe impact.
Statistical data reveals a disturbing trend: extractable groundwater resources have plummeted from approximately 2,800 crore cubic meters in 2013 to about 2,000 crore cubic meters in 2023, representing a loss of roughly 800 crore cubic meters within a single decade. This rapid depletion stems from multiple factors including uncontrolled urbanization, reduced rainwater infiltration due to widespread concretization, and rampant groundwater extraction by households, industries, and construction projects.
Barman emphasized that their system provides dual benefits: it not only replenishes groundwater but also helps mitigate urban flooding by absorbing rooftop runoff that would otherwise overwhelm surface drains during heavy rainfall. He described the model as "eco-friendly, low-cost, and easily replicable" across the city, including other government offices, noting that awareness remains the crucial factor for wider adoption.
The project, officially inaugurated on July 30 by AERC chairperson Kumar Sanjay Krishna along with member (law) Alokeswar Bhattacharyya, highlights the implementation gap in Guwahati's water management policies. While the Guwahati Municipal Corporation mandates rainwater harvesting systems for building permissions, enforcement remains weak, leaving many structures without this essential infrastructure.
Meanwhile, residents across numerous city areas continue struggling with inconsistent municipal water supply, forcing dependence on private suppliers and individual borewells. Many households lack tap water connections entirely, while even connected localities face frequent disruptions due to pipeline leaks that take considerable time to repair.
The AERC officer concluded that their rainwater harvesting system demonstrates a practical model that other institutions and households can emulate. It proves that dependence on increasingly deeper borewells can be reduced while actively contributing to replenishing the city's vanishing water reserves, offering hope for a more water-secure future for Guwahati.
