AN EMPIRICAL PARAMETRIC EQUATION FOR POINT WATER INFILTRATION INTO BARE SEALING SOILS UNDER SIMULATED RAINFALL
Abstract
In applied hydrology it is useful to estimate the infiltration phase with a model having a small number of parameters. Pragmatically speaking, the most important feature about parameters of empirical equations is not their precise meaning in terms of the physics of water flow through porous media, but the actual possibility of predicting their values on a reliable and consistent basis. The realization of this possibility was satisfactorily accomplished here, under the rather restrictive circumstances surrounding the experimental phase of the research. In the context of this study, parametric modeling meant an attempt at the definition of relationships between basic soil physical properties usually found in soil survey reports and soil hydrologic response, in terms of point water infiltration, to a constant high intensity rainfall input, when a seal was allowed to develop over the soil surface. This modeling approach involved model formulation, data collection and processing, evaluation of the model parameters by objective best fit procedures, regionalization of the model parameters, sensitivity analyses and, finally, prediction of the infiltration process into the sealing soil. The experimental phase consisted of infiltration tests conducted in the laboratory, using a small rainfall simulator with Veejet 80100 nozzles, and soil beds simulating small plots of bare, freshly cultivated soils, with no impeding stratum below. A parametric equation for point water infiltration evolved from modifications made in the equations originally proposed by Smith (1972) and Swartzendruber (1974) for surface stable soils.
Degree
Ph.D.
Subject Area
Agronomy|Cartography
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