Caracterização Hidrodinâmica dos Solos da Bacia Experimental do Riacho Guaraíra Utilizando o Método Beerkan

Abstract

Knowledge of hydraulic properties of soil, such as the water retention and hydraulic conductivity curves, is indispensable for water and sediment transport modeling. Thus, in this work, a methodology used to obtain hydrodynamic soil properties, known as Beerkan, is presented to spatially characterize the main soil hydrodynamic characteristics, i.e., saturated hydraulic conductivity, porosity, and water retention in the soil, for the Guaraira River Experimental Basin, located in the coastal zone of northeastern Brazil. Disturbed soil samples were collected and infiltration tests were accomplished in a regular grid of 196 cells in the basin with 200 m spacing. This method was applied to two soil types (Argisols and Spodosols) with different textural classification (sand, loamy sand, sandy loam). For the hydrodynamic characterization, the shape and the normalization parameters of the θ(h) and of K(θ) curves were determined. The shape parameters depend upon the soil texture and they were obtained from the cumulative particle size distribution curve; the normalization parameters depend on soil structure and they were obtained from the infiltration experiments using the simple ring infiltrometer. The obtained results showed that the values of sorptivity (S) and saturated hydraulic conductivity (Ks) are slightly higher for soils with a lower sand percentage. It was also verified that S and Ks values are higher for the Spodosols, showing that Spodosols are more permeable than Argisols, for any textural class analyzed. Finally, the Beerkan method showed to be a promising method and easily applied to modeling three-dimensional infiltration in the field, as