Numerical modelling of water infiltration into the three components of porosity of a vertisol from Guadeloupe

• Published in: Journal of hydrology (Amsterdam) 1999-08, Vol.221 (1), p.1-19
• Main Authors: Ruy, S., Di Pietro, L., Cabidoche, Y.M.
• Format: Article
• Language: English
• Subjects: Crack; Earth sciences; Earth, ocean, space; Exact sciences and technology; Guadeloupe; Hydrogeology; Hydrology. Hydrogeology; Infiltration; Macro-porosity; macropores; mathematical models; Preferential flow; Swelling clay soil; Vertisol; Vertisols
• ISSN: 0022-1694; 1879-2707
• DOI: 10.1016/S0022-1694(99)00080-3

We present a mechanistic model of soil deformation and water infiltration into a Vertisol of Guadeloupe (French West Indies), which accounts for the three components of porosity of this soil (matric, structural and macro-cracks). Time and space scales are respectively of several hours and the prism delimited by macro-cracks. The model accounts for water movements from the structural porosity and from the macro-cracks into the matric porosity. It simulates the non-equidimensional deformations of the prism resulting from water storage in the matric porosity. Inputs of the model, measured in the laboratory, are the shrinkage curve, the retention curve and the hydraulic conductivity of the matric porosity. The anisotropy ratio of the soil deformation was measured in situ. Experiments were conducted in situ to provide structural parameters and data to fit and test the model. It is possible to find a unique set of parameters for each experiment. However, parameters significantly differ from one experiment to another. The model shows that the structural water flow regulates the partition of water infiltrating within the prism and of water flowing in the macro-cracks. The model does not accurately predict water infiltration because of a poor modelling of water flow in the structural porosity.