@article{fdi:010053597,
  title = {{O}rigins of streamflow in a crystalline basement catchment in a sub-humid {S}udanian zone : the {D}onga basin ({B}enin, {W}est {A}frica) {I}nter-annual variability of water budget},
  author = {{S}{\'e}guis, {L}uc and {K}amagat{\'e}, {B}. and {F}avreau, {G}uillaume and {D}escloitres, {M}arc and {S}eidel, {J}. {L}. and {G}alle, {S}ylvie and {P}eugeot, {C}hristophe and {G}osset, {M}arielle and {L}e {B}arb{\'e}, {L}uc and {M}alinur, {F}red and {V}an {E}xter, {S}. and {A}rjounin, {M}arc and {B}oubkraoui, {S}t{\'e}phane and {W}ubda, {M}axime},
  editor = {},
  language = {{ENG}},
  abstract = {{D}uring the last quarter of the 20th century, {W}est {A}frica underwent a particularly intense and generalized drought. {D}uring this period, the biggest drops in streamflow were observed in the {S}udanian zone rather than in the {S}ahelian zone, but the reasons are still poorly understood. {I}n 2000, a meso-scale hydrological observatory was set up in the sub-humid {S}udanian zone of the {U}pper {O}ueme {V}alley ({B}enin). {T}hree embedded catchments of 12-586 km(2) located on a crystalline bedrock were intensively instrumented to document the different terms of the water budget and to identify the main streamflow generating processes and base-flow mechanisms at different scales. {G}eophysical, hydrological and geochemical data were collected throughout the catchments from 2002 to 2006. {C}rossing these data helped define their hydrological functioning. {T}he region has seasonal streamflow, and the permanent groundwater in the weathered mantle does not drain to rivers, instead, seasonal perched groundwaters are the major contributor to annual streamflow. {T}he perched groundwaters are mainly located in seasonally waterlogged sandy layers in the headwater bottom-lands called bas-fonds in {F}rench-speaking {W}est {A}frica of 1st order streams. {D}uring the period 2003-2006, regolith groundwater recharge ranged between 10% and 15% of the annual rainfall depth. {D}epletion of permanent groundwater during the dry season is probably explained by local evapotranspiration which was seen not to be limited to gallery forests. {D}uring the 4-year study period, a reduction of 20% in annual rainfall led to a 50% reduction in streamflow. {T}his reduction was observed in the two components of the flow: direct runoff and drainage of perched groundwater. {T}hanks to the comprehensive dataset obtained, the results obtained for the {D}onga experimental catchment are now being extrapolated to the whole upper {O}ueme valley, which can be considered as representative of sub-humid {S}udanian rivers flowing on a crystalline basement, for example, the upper courses of several major {W}est {A}frican rivers ({S}enegal, {N}iger, {B}ani, and {V}olta).},
  keywords = {{P}erched aquifer ; {S}treamflow decomposition ; {W}ater isotopes ; {W}est {A}frica ; {S}udanian climate ; {B}asement catchment},
  booktitle = {},
  journal = {{J}ournal of {H}ydrology},
  volume = {402},
  numero = {1-2},
  pages = {1--13},
  ISSN = {0022-1694},
  year = {2011},
  DOI = {10.1016/j.jhydrol.2011.01.054},
  URL = {https://www.documentation.ird.fr/hor/fdi:010053597},
}