Physical-hydric characterization and modeling of saturated hydraulic conductivity of dune sands with and without vegetation

ABSTRACT

The amount of data available on the effects of induced stabilization of dunes on their physical-hydric properties is limited, especially in coastal dunes of Ceará. In this sense, this research sought to characterize these properties in dunes located on the sideroad of a highway in the city of Aquiraz, coastal region of Ceará, whose stretch was stabilized through the use of coconut straw (straw checkerboard) in which there was later vegetation development. Deformed and undisturbed samples were obtained from the soil surface layer (0–0.15 m) to determine the following parameters: particle size, bulk density, true density, saturated hydraulic conductivity (Ks), macro and microporosity, and soil characteristic curve. Four empirical equations were also evaluated for indirect estimation of saturated hydraulic conductivity through particle size parameters, comparing values measured and modeled by the equations. The results indicated that, in terms of characterization, the physical properties of the soil without cover have the same order of magnitude as the soil with vegetation. On the other hand, the T test, for comparing means, indicated values of real density, total porosity, and macroporosity that were statistically different for the two types of soil. Comparing the hydraulic parameters of both soils, it was observed that the hydraulic conductivity (normal and transformed) and the characteristic curve also have similar results. Within the applied empirical equations, it was observed that the values of Ks estimated by the Hazen (modified) and the Beyer models were closest to those measured in the laboratory.

Keywords:
soil; dune; characterization; hydraulic conductivity; empirical methods