TY - JOUR
T1 - Tracing groundwater dynamics in the Chakari Basin, Afghanistan
T2 - A multi-tracer study with socio-environmental implications
AU - Zaryab, Abdulhalim
AU - Mack, Thomas J.
AU - Farahmand, Asadullah
AU - Ali, Shakir
AU - Nikpeyman, Vahid
AU - Nikpeyman, Yaser
AU - Cook, Peter G.
PY - 2026/2
Y1 - 2026/2
N2 - Study region: The Chakari Basin in southeastern Kabul, Afghanistan, is an arid to semi-arid region where groundwater from springs, wells, and karezes serves as the primary water resource. Despite its importance, the hydrogeological characteristics of the basin, including groundwater origin, flow pathways, and age, remain poorly constrained due to long-standing infrastructural, technical, and socio-political limitations. Study focus: This study applies a comprehensive multi-tracer approach to overcome these data gaps and evaluate groundwater dynamics in the Chakari Basin. We analyzed stable isotopes (delta 2H, delta 18O), radioactive tracers (3H, 14C), anthropogenic atmospheric trace gases (CFC-11, CFC-12, CFC113, SF6), and noble gases (4He, 22Ne) to identify recharge sources, quantify groundwater residence times, and assess mixing processes and anthropogenic influences. The integrated dataset provides the first systematic assessment of groundwater age and recharge conditions for the basin. New hydrological insight: Stable isotope compositions indicate meteoric recharge originating from relatively high elevations. CFC-based groundwater ages of approximately 10-40 years reveal that a substantial fraction of the basin's groundwater reflects multi-decadal recharge. Several tracers showed region-specific limitations, including anomalously high SF6 likely linked to recent atmospheric contamination, dilution of 1 4C activity by carbonate dissolution, and mostly nondetectable 3H consistent with older or deeper flow components. Noble gas excesses, particularly 22Ne, corroborate the multi-decadal residence times and indicate partial mixing along flow paths. These findings provide the first integrated groundwater age framework for the Chakari Basin and highlight the value of tracer cross-validation for robust hydrogeological interpretation in regions facing climatic stress, rising water demand, and vulnerability to contamination.
AB - Study region: The Chakari Basin in southeastern Kabul, Afghanistan, is an arid to semi-arid region where groundwater from springs, wells, and karezes serves as the primary water resource. Despite its importance, the hydrogeological characteristics of the basin, including groundwater origin, flow pathways, and age, remain poorly constrained due to long-standing infrastructural, technical, and socio-political limitations. Study focus: This study applies a comprehensive multi-tracer approach to overcome these data gaps and evaluate groundwater dynamics in the Chakari Basin. We analyzed stable isotopes (delta 2H, delta 18O), radioactive tracers (3H, 14C), anthropogenic atmospheric trace gases (CFC-11, CFC-12, CFC113, SF6), and noble gases (4He, 22Ne) to identify recharge sources, quantify groundwater residence times, and assess mixing processes and anthropogenic influences. The integrated dataset provides the first systematic assessment of groundwater age and recharge conditions for the basin. New hydrological insight: Stable isotope compositions indicate meteoric recharge originating from relatively high elevations. CFC-based groundwater ages of approximately 10-40 years reveal that a substantial fraction of the basin's groundwater reflects multi-decadal recharge. Several tracers showed region-specific limitations, including anomalously high SF6 likely linked to recent atmospheric contamination, dilution of 1 4C activity by carbonate dissolution, and mostly nondetectable 3H consistent with older or deeper flow components. Noble gas excesses, particularly 22Ne, corroborate the multi-decadal residence times and indicate partial mixing along flow paths. These findings provide the first integrated groundwater age framework for the Chakari Basin and highlight the value of tracer cross-validation for robust hydrogeological interpretation in regions facing climatic stress, rising water demand, and vulnerability to contamination.
KW - Afghanistan
KW - Chakari Basin
KW - Environmental tracers
KW - Groundwater dating
KW - Noble gases
U2 - 10.1016/j.ejrh.2025.103049
DO - 10.1016/j.ejrh.2025.103049
M3 - Article
SN - 2214-5818
VL - 63
JO - Journal of Hydrology: Regional Studies
JF - Journal of Hydrology: Regional Studies
M1 - 103049
ER -