EMPIRICAL EVALUATION OF THE RELATIONSHIP BETWEEN RAINFALL AND THE DEGREE OF SATURATION OF SHALLOW SOILS

ABSTRACT: Experimental data referring to the degree of saturation of a shallow soil show that it is time-varying as a consequence to different weather conditions. In many real applications it is useful to directly cor-relate the degree of saturation of the soil with rainfall amounts. The paper deals with the in-situ measurements of soil water content and the description of a simplified empirical model, which allows to obtain the degree of saturation using the readily available climate data on air temperature and rainfall depths as driving variables. The experimental measurements of the soil water content at a site in San Pietro Capofiume, Emilia Romagna Region, Northern Italy, are compared with the results of the simplified model over an observation period of almost two years. The model requires a separate calibration for each point where the degree of saturation is to be computed, but the different parameters seem to have a certain trend with soil depth. Moreover a discussion on the calibration of the model parameters is carried out in order to clarify how the input data have been cho-sen.