Groundwater recharge sources and salinity in northwest India

Lapworth, D.J. ORCID: https://orcid.org/0000-0001-7838-7960; Krishan, G.; MacDonald, A. ORCID: https://orcid.org/0000-0001-6636-1499; Rao, M.. 2023 Groundwater recharge sources and salinity in northwest India. [Lecture] In: The 50th Congress of the International Association of Hydrogeologists, Cape Town, South Africa, 17-22 Sep 2023. (Unpublished)

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Abstract/Summary

Groundwater is intensively abstracted for irrigation in Punjab (India) with declining groundwater levels a growing concern in some areas. Water isotopes and SEC are used in this paper to investigate groundwater recharge sources and processes in a catchment with a history of high groundwater abstraction and canal irrigation. High frequency (every 10 days) samples for water stable isotope analysis (δ18O and δ2H) and SEC were sampled from a dense network of shallow (<50 m) and deep (>100 m) hand pumps and tube wells in Bist Doab, northern Punjab between 2009 – 2014. Groundwater recharge in this part of northern Punjab is dominated by meteoric sources. However, a significant proportion of surface water recharge sources were delineated in a small proportion of sites located in close proximity to some canals and rivers. High frequency isotope observations indicate rapid changes in groundwater recharge sources linked to post-monsoon pumping and seasonal connectivity to surface water inputs even at some deep sites. Some rapid changes are likely linked to poor well integrity and anulus flow, highlighting the risk to groundwater sources from surface water ingress. Shallow groundwaters had significantly higher SEC compared to deeper observations (p=0.0002). While absolute SEC values in shallow groundwater are still relatively low compared to international drinking water guidelines, based on previously published mean residence time of (<50 years) in shallow groundwater the high rate of change (2.5-10% per year) is of concern and suggests that the current salt inputs to groundwater are not sustainable in the medium-long term

Item Type:	Publication - Conference Item (Lecture)
Additional Keywords:	IGRD, GroundwaterBGS, Groundwater
Date made live:	18 Dec 2023 12:12 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/536480

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