Causes and sustainable solutions of pre-monsoon water scarcity crisis in Bengaluru city, India

Abstract

Bengaluru, India’s burgeoning metropolis, faced a pressing water scarcity crisis during the lean monsoon period in 2023–2024. This paper investigates the root causes of this crisis and proposes viable solutions for effective mitigation. The city has experienced 37.75% less rainfall in 2023 compared to the decadal average annual rainfall. The stage of groundwater extraction has increased from 193% in the year 2022 to 217% in 2023, and the city is categorized as “over-exploited.” The study reveals that the rainfall deficit in 2023, coupled with escalating groundwater extraction rates and adverse land use practices, is exacerbating the depletion of aquifers and drying up of borewells. The demand of water in the city is estimated to be 1891 million liters per day (MLD) out of which the current supply after losses is calculated to be 1273 MLD leading to a deficit of 618 MLD. Furthermore, areas lacking a comprehensive Cauvery water supply exhibit deeper water levels, highlighting disparities in access to groundwater resources. To address these challenges, the paper suggests a multifaceted approach encompassing regulatory measures, technological interventions, and community engagement. Bengaluru’s water crisis stems from rapid urbanization, population growth, and groundwater depletion, requiring immediate and long-term interventions. Removing encroachments on lakes and desilting them can enhance groundwater recharge and mitigate flooding. Utilizing treated sewage water from BWSSB’s STPs for lake recharge and public use can conserve freshwater. Large residential complexes must implement recharge trenches, while bulk water suppliers should be regulated to prevent over-extraction. Enforcing rainwater harvesting laws, penalizing freshwater misuse, and promoting water-saving fixtures can further reduce demand. Additionally, exploring alternative surface water sources like Yettinahole and Mekadatu projects will help ensure Bengaluru’s long-term water sustainability.