Hydraulic Modeling in the Vadose Zone of an Agricultural Area under Water Stress (M’nasra, Morocco)

Abstract

Due to extensive irrigation and successive drought periods, most aquifers of north Morocco are overexploited. Soil-water characteristic curve and soil hydraulic properties are important for agricultural water management and modeling of the water flow in unsaturated soils. The experimental determination of some of these parameters in the laboratory or in-situ requires expensive equipment and time consuming. The main objective of this work is to predict the water distribution process in unsaturated soil, based, on the one hand, on the hydrodynamic parameters ( $$\theta_\mathrm{r}$$ , $$\theta_\mathrm{s}$$ , $$n$$ , $$\alpha$$ , $$K_\mathrm{s}$$ ) and, on the other hand, by using the two-dimensional numerical software Hydrus-2D model, from in situ measurements of cumulative infiltration and water content. The experimental tests were carried out in the experimental station of the M’nasra area located in the north of Morocco by using the disc infiltrometer which allows measuring the infiltration flow in the soil. The results obtained from this estimation of the parameters allow simulating and controlling the evolution of water flow and solute transport in the unsaturated zone. Furthermore, the results of the statistical analysis have also shown the feasibility of the Hydrus-2D to simulate the movements of water in the vadose zone.