Journal of
Soil Science and Environmental Management

  • Abbreviation: J. Soil Sci. Environ. Manage.
  • Language: English
  • ISSN: 2141-2391
  • DOI: 10.5897/JSSEM
  • Start Year: 2010
  • Published Articles: 287

Full Length Research Paper

Temporal evolution of the hydrodynamic behaviour of sandy deposits in the Sahelian part of Burkina Faso

D. Niang1*, A. Mermoud2, H. Yacouba1 and O. Ribolzi3
1International Institute for Water and Environmental Engineering, 1, rue de la Science, 01 BP 594, Ouagadougou 01, Burkina Faso. 2Environmental Engineering Institute, Swiss Federal Inst. of Technology, EPFL, ENAC, IIE, ECHO, Station 2, 1015 Lausanne, Switzerland. 3Laboratoire des Mécanismes de Transferts en Géologie, Université de Toulouse, 14, avenue Edouard Belin, F-31400, Toulouse, France.
Email: [email protected]

  •  Accepted: 24 July 2012
  •  Published: 31 December 2012

Abstract

Sahelian areas of Burkina Faso are confronted with various natural and anthropogenic processes that can lead to degraded areas where the vegetation is localized mainly in units called "sandy deposits”. Those deposits are subject to temporal dynamics that greatly impact their hydrodynamic behaviour; the initial drying crust evolves frequently to a drying crust in transition, and ultimately to an erosion crust (according to the crust classification established by Casenave and Valentin (1992)). To better apprehend the temporal evolution and the hydrodynamic behaviour of the sandy deposits, various field measurements have been performed on seven monitoring sites installed in three contrasting zones corresponding to the three crust types. The sites located on erosion crusts and on drying crusts in transition are characterized by a low infiltration capacity which favours run-off (run-off coefficients between 50 and 80%). The sites situated on drying crusts are characterized by a high hydraulic conductivity and infiltration capacity, as well as, relatively low run-off coefficients (smaller than 40%); the water storage in the root zone is more important and water infiltrates deeper into the soil and, occasionally, drains below the depth of 50 cm. The study confirms that soil properties are subject to important temporal evolution, resulting in a strong degradation.

 

Key words: Aeolian sandy deposits, infiltration, run-off, soil hydrodynamic, soil physical properties, soil surface crusting, Sahel.