Taylor & Francis Group
Browse
thsj_a_1937630_sm5432.docx (7.17 MB)

Groundwater recharge from heavy rainfall in the southwestern Lake Chad Basin: evidence from isotopic observations

Download (7.17 MB)
Version 2 2021-07-07, 16:00
Version 1 2021-06-03, 08:20
journal contribution
posted on 2021-07-07, 16:00 authored by Ibrahim Baba Goni, Richard G. Taylor, Guillaume Favreau, Mohammad Shamsudduha, Yahaya Nazoumou, Benjamin Ngounou Ngatcha

We examine groundwater recharge processes and their relationship to rainfall intensity in the semi-arid, southwestern Lake Chad Basin of Nigeria using a newly compiled database of stable isotope data (δ2H, δ18O) from groundwater and rainfall. δ18O signatures in groundwater proximate to surface waters are enriched in 18O relative to regional rainfall and trace focused groundwater recharge from evaporated waters via ephemeral river discharge and Lake Chad; groundwater remote from river channels is comparatively depleted and associated with diffuse recharge, often via sand dunes. Stable isotope ratios of O and H (δ2H, δ18O) in groundwater samples regress to a value along the local meteoric waterline that is depleted relative to weighted mean composition of rainfall, consistent with rainfall exceeding the 60th percentile of monthly precipitation intensity. The observed bias in groundwater recharge to heavy monthly rainfall suggests that the intensification of tropical rainfall under global warming favours groundwater recharge in this basin.

Funding

This work was supported by the Natural Environment Research Council [NE/M008932/1].

History

Usage metrics

    Hydrological Sciences Journal

    Licence

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC