DETERMINING THE SOIL MOISTURE-TENSION PARAMETER IN THE GREEN-AMPT INFILTRATION EQUATION FOR RUNOFF-EROSION MODELING

摘要

A method to determine the main parameters in the Green-Ampt infiltration equation isproposed based on indoor experiments carried out with two different samples ofsand, and then the method is tested with field data collected in a semiarid region inBrazil. The results proved that the soil moisture content and suction could beaggregated in one parameter called moisture-tension parameter Ns, which showed tohave a typical change according to the time variable. Thus, a relationship betweenthe number of consecutive dry days and the parameter Ns was presented for a testfield of a semiarid region in Brazil and a method was given to determine theparameter for the areas where measuring systems are not available on site.