@article{fdi:010037606,
  title = {{D}eep infiltration through a sandy alluvial fan in semiarid {N}iger inferred from electrical conductivity survey, vadose zone chemistry and hydrological modelling},
  author = {{M}assuel, {S}ylvain and {F}avreau, {G}uillaume and {D}escloitres, {M}arc and {L}e {T}roquer, {Y}ann and {A}lbouy, {Y}ves and {C}appelaere, {B}ernard},
  editor = {},
  language = {{ENG}},
  abstract = {{I}n semiarid southwestern {N}iger, most of the groundwater recharge is indirect and occurs through endoreic ponds. {E}lsewhere in the landscape, there is no evidence of deep infiltration, with a possible exception for gullies and alluvial fans on sandy slopes. {I}n order to verify this hypothesis, a detailed geophysical and geochemical survey was conducted on a large, representative mid-slope fan (6 ha). {A}t this site, distributed hydrological modelling conducted over the encompassing endoreic catchment (190 ha) showed high losses of runoff water by infiltration. {E}lectromagnetic mapping and 2-{D} electrical imaging survey were used to investigate the 35 in deep vadose zone; in addition, 8 boreholes were drilled following the geophysical survey to constrain the interpretation. {V}ariations in apparent electrical conductivity measured in boreholes appear to be mainly linked with changes in the soil solution mineralization. {A}n extrapolation throughout the area shows that apparent electrical conductivity of the ground is systematically lower below channels; this suggests localised leaching through the unsaturated zone. {A} physically-based, 2-{D} distributed hydrologic model was used to estimate the amount of surface water loss by infiltration for the 1992-2002 period. {D}epending on year, infiltrated volumes range from 1000 to 24000 m(3). {T}his represents between 5% and 16% of the runoff that reaches the final outlet of the basin, an endoreic valley bottom pond where recharge to the aquifer has been shown to occur. {B}ecause leaching of the vadose zone is observed down to a depth of 10 m below channels, episodic groundwater recharge through sandy mid-slope fans is highly probable during rainy years. (c) 2006 {E}lsevier {B}.{V}. {A}ll rights reserved.},
  keywords = {{N}iger ; semiarid area ; infiltration ; local recharge ; alluvial fan ; geophysical survey ; unsaturated zone chemistry},
  booktitle = {},
  journal = {{C}atena},
  volume = {67},
  numero = {2},
  pages = {105--118},
  ISSN = {0341-8162},
  year = {2006},
  DOI = {10.1016/j.catena.2006.02.009},
  URL = {https://www.documentation.ird.fr/hor/fdi:010037606},
}