Journal cover Journal topic
Hydrology and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 4.936 IF 4.936
  • IF 5-year value: 5.615 IF 5-year
    5.615
  • CiteScore value: 4.94 CiteScore
    4.94
  • SNIP value: 1.612 SNIP 1.612
  • IPP value: 4.70 IPP 4.70
  • SJR value: 2.134 SJR 2.134
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 107 Scimago H
    index 107
  • h5-index value: 63 h5-index 63
Volume 17, issue 12
Hydrol. Earth Syst. Sci., 17, 5079–5096, 2013
https://doi.org/10.5194/hess-17-5079-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
Hydrol. Earth Syst. Sci., 17, 5079–5096, 2013
https://doi.org/10.5194/hess-17-5079-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 13 Dec 2013

Research article | 13 Dec 2013

Interplay of riparian forest and groundwater in the hillslope hydrology of Sudanian West Africa (northern Benin)

A. Richard1, S. Galle2, M. Descloitres2, J.-M. Cohard1, J.-P. Vandervaere1, L. Séguis3, and C. Peugeot3 A. Richard et al.
  • 1UJF-Grenoble 1, LTHE, UMR5564, CNRS – UJF-Grenoble 1/G-INP/IRD, 38041 Grenoble, France
  • 2IRD, LTHE, UMR5564, CNRS – UJF-Grenoble 1/G-INP/IRD, 38041 Grenoble, France
  • 3IRD, HSM, UMR5569, CNRS – UM1/UM2), 34095 Montpellier, France

Abstract. Forests are thought to play an important role in the regional dynamics of the West African monsoon, through their capacity to extract water from a permanent and deep groundwater table to the atmosphere even during the dry season. It should be the case for riparian forests too, as these streambank forests are key landscape elements in Sudanian West Africa. The interplay of riparian forest and groundwater in the local hydrodynamics was investigated, by quantifying their contribution to the water balance. Field observations from a comprehensively instrumented hillslope in northern Benin were used. Particular attention was paid to measurements of actual evapotranspiration, soil water and deep groundwater levels. A vertical 2-D hydrological modelling approach using the Hydrus software was used as a testing tool to understand the interactions between the riparian area and the groundwater. The model was calibrated and evaluated using a multi-criteria approach (reference simulation). A virtual experiment, including three other simulations, was designed (no forest, no groundwater, neither forest nor groundwater).

The model correctly simulated the hydrodynamics of the hillslope regarding vadose zone dynamics, deep groundwater fluctuation and actual evapotranspiration dynamics. The virtual experiment showed that the riparian forest transpiration depleted the deep groundwater table level and disconnected it from the river, which is consistent with the observations. The riparian forest and the deep groundwater table actually form an interacting transpiration system: the high transpiration rate in the riparian area was shown to be due to the existence of the water table, supplied by downslope lateral water flows within the hillslope soil layer. The simulated riparian transpiration rate was practically steady all year long, around 7.6 mm d−1. This rate lies within high-end values of similar study results. The riparian forest as simulated here contributes to 37% of the annual hillslope transpiration, and reaches 57% in the dry season, whereas it only covers 5% of the hillslope area.

Publications Copernicus
Download
Citation