TY - JOUR
T1 - Vadose zone water stable isotope profiles for assessing groundwater recharge
T2 - Sensitivity to seasonal soil sampling
AU - Boumaiza, Lamine
AU - Chesnaux, Romain
AU - Drias, Tarek
AU - Stotler, Randy L.
AU - Skrzypek, Grzegorz
AU - Gillon, Marina
AU - Wanke, Heike
AU - Johannesson, Karen H.
AU - Stumpp, Christine
N1 - Funding Information:
The authors thank Natural Sciences and Engineering Research Council of Canada that have funded this project through NSERC-Discovery Grand (RGPIN/07117) held by Prof. Romain Chesnaux. The authors also acknowledge the financial support from the Comite de liaison institutionnel of the Université du Quebec à Chicoutimi (Grant number CLI-57403 held by Dr. Lamine Boumaiza). The authors would like to thank the Algerian National Agency of Water Resources at El-Madher (Batna) for providing free access to the investigated site.
Funding Information:
The authors thank Natural Sciences and Engineering Research Council of Canada that have funded this project through NSERC-Discovery Grand (RGPIN/07117) held by Prof. Romain Chesnaux. The authors also acknowledge the financial support from the Comite de liaison institutionnel of the Université du Quebec à Chicoutimi (Grant number CLI-57403 held by Dr. Lamine Boumaiza). The authors would like to thank the Algerian National Agency of Water Resources at El-Madher (Batna) for providing free access to the investigated site.
Publisher Copyright:
© 2023 Elsevier B.V.
PY - 2023/11
Y1 - 2023/11
N2 - Groundwater recharge is widely recognized as being the most important parameter for the sustainable management of water resources. In semiarid environments, groundwater recharge can be quantified using the piston displacement method (PDM). From a single soil sampling campaign, the PDM relies on linking the deeper vadose zone soil pore water stable isotope composition (δ2HH2O and δ18OH2O) to the local meteoric water line (LMWL). However, the isotopic composition of precipitation changes seasonally, influencing the water isotope composition of the vadose zone over time. Thus, it is important to test whether the PDM is sensitive to seasonal soil sampling and whether the assessed recharge rate is independent of the time of sampling. This study investigates the effect of seasonal soil sampling on the distribution of vadose zone stable isotope composition to determine whether the sampling time influences the estimate of recharge rate from PDM. Soil samples were obtained along vertical profiles through the vadose zone in a semiarid region during the spring, summer, and autumn seasons. Specifically, the δ2HH2O and δ18OH2O of the soil pore water were determined along vertical profiles, and the PDM was applied to quantify the annual recharge. The δ2HH2O and δ18OH2O values range from −7.3 to −3.5 ‰ and from −54.4 to +7.41 ‰, respectively, and plot along a continuum with a slope less than the LMWL. Samples from deeper in the vadose zone profile had distinct ranges in isotopic composition between the three soil sampling campaigns, with isotopic composition of spring sampling dominated by lower values and those from autumn with higher values. Despite these differences, the resulting annual recharge rates from the different sampling campaigns are comparable (1.5 to 2 % of annual precipitation). Even though the pore water isotopic composition changed over time, the shift between the deeper vadose zone isotopic compositions and the LMWL remained relatively constant, leading to a similar recharge estimate over time. Therefore, the PDM-based recharge assessment in the tested semiarid environment is independent of the sampling time, which indicates that sampling for assessing groundwater recharge can be undertaken during any season.
AB - Groundwater recharge is widely recognized as being the most important parameter for the sustainable management of water resources. In semiarid environments, groundwater recharge can be quantified using the piston displacement method (PDM). From a single soil sampling campaign, the PDM relies on linking the deeper vadose zone soil pore water stable isotope composition (δ2HH2O and δ18OH2O) to the local meteoric water line (LMWL). However, the isotopic composition of precipitation changes seasonally, influencing the water isotope composition of the vadose zone over time. Thus, it is important to test whether the PDM is sensitive to seasonal soil sampling and whether the assessed recharge rate is independent of the time of sampling. This study investigates the effect of seasonal soil sampling on the distribution of vadose zone stable isotope composition to determine whether the sampling time influences the estimate of recharge rate from PDM. Soil samples were obtained along vertical profiles through the vadose zone in a semiarid region during the spring, summer, and autumn seasons. Specifically, the δ2HH2O and δ18OH2O of the soil pore water were determined along vertical profiles, and the PDM was applied to quantify the annual recharge. The δ2HH2O and δ18OH2O values range from −7.3 to −3.5 ‰ and from −54.4 to +7.41 ‰, respectively, and plot along a continuum with a slope less than the LMWL. Samples from deeper in the vadose zone profile had distinct ranges in isotopic composition between the three soil sampling campaigns, with isotopic composition of spring sampling dominated by lower values and those from autumn with higher values. Despite these differences, the resulting annual recharge rates from the different sampling campaigns are comparable (1.5 to 2 % of annual precipitation). Even though the pore water isotopic composition changed over time, the shift between the deeper vadose zone isotopic compositions and the LMWL remained relatively constant, leading to a similar recharge estimate over time. Therefore, the PDM-based recharge assessment in the tested semiarid environment is independent of the sampling time, which indicates that sampling for assessing groundwater recharge can be undertaken during any season.
KW - Recharge, Piston displacement method
KW - Semiarid
KW - Soil
KW - Vadose zone
KW - δH and δO
UR - http://www.scopus.com/inward/record.url?scp=85174971796&partnerID=8YFLogxK
U2 - 10.1016/j.jhydrol.2023.130291
DO - 10.1016/j.jhydrol.2023.130291
M3 - Article
AN - SCOPUS:85174971796
SN - 0022-1694
VL - 626
JO - Journal of Hydrology
JF - Journal of Hydrology
M1 - 130291
ER -