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Assessing the role of groundwater recharge from tanks in crystalline bedrock aquifers in Karnataka, India, using hydrochemical tracers

Brauns, B and Chattopadhyay, S and Lapworth, DJ and Loveless, SE and MacDonald, AM and McKenzie, AA and Sekhar, M and Nara, SNV and Srinivasan, V (2022) Assessing the role of groundwater recharge from tanks in crystalline bedrock aquifers in Karnataka, India, using hydrochemical tracers. In: Journal of Hydrology X, 15 .

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Official URL: https://doi.org/10.1016/j.hydroa.2022.100121


The majority of India's rural drinking water supply is sourced from groundwater, which also plays a critical role in irrigated agriculture, supporting the livelihoods of millions of users. However, recent high abstractions are threatening the sustainable use of groundwater, and action is needed to ensure continued supply. Increased managed aquifer recharge (MAR) using the > 200,000 existing tanks (artificially created surface water bodies) is one of the Indian government's key initiatives to combat declining groundwater levels. However, few studies have directly examined the effectiveness of tank recharge, particularly in the complex fractured hydrogeology of Peninsular India. To address this gap, this study examined the impact of tanks in three crystalline bedrock catchments in Karnataka, southern India, by analysing the isotopic and hydrochemical composition of surface waters and groundwaters, combined with groundwater level observations. The results indicate that tanks have limited impact on regional groundwater recharge and quality in rural areas, where recharge from precipitation and groundwater recycling from irrigation dominate the recharge signal. In the urban setting (Bengaluru), impermeable surfaces increased the relative effect of recharge from point sources such as tanks and rivers, but where present, pipe leakage from public-water-supply accounted for the majority of recharge. Shallow groundwater levels in the inner parts of the city may lead to groundwater discharge to tanks, particularly in the dry season. We conclude that the importance of aquifer recharge from tanks is limited compared to other recharge sources and highly dependent on the specific setting. Additional studies to quantify tank recharge and revisions to the current guidelines for national groundwater recharge estimations, using a less generalised approach, are recommended to avoid over-estimating the role tanks play in groundwater recharge. © 2022 British Geological Survey (c) UKRI 2022. All rights reserved

Item Type: Journal Article
Publication: Journal of Hydrology X
Publisher: Elsevier B.V.
Additional Information: The copyright for this article belongs to Authors
Keywords: Aquifers; Catchments; Fracture; Groundwater resources; Hydrochemistry; Hydrogeology; Isotopes; Potable water; Rural areas; Surface waters; Tanks (containers); Water supply, Bedrock aquifers; Crystalline bedrocks; Fractured rock; Ground water level; Ground water recharge; Hydrochemical tracers; India; Karnataka; Stable isotopes; Tank, Recharging (underground waters), aquifer; bedrock; crystalline rock; drinking water; hydrogeology; pipe; recycling; water supply, Bengaluru; India; Karnataka
Department/Centre: Division of Interdisciplinary Sciences > Interdisciplinary Centre for Water Research
Division of Mechanical Sciences > Civil Engineering
Date Deposited: 17 Feb 2022 06:37
Last Modified: 17 Feb 2022 06:37
URI: http://eprints.iisc.ac.in/id/eprint/71308

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