Initial Soil Moisture Conditions Research Articles

A MODIFIED HORTON EQUATION FOR INFILTRATION DURING INTERMITTENT RAINFALL

ABSTRACT A simple infiltration concept based on Horton's infiltration equation has been developed for use in mathematical rainfall-runoff modelling. Horton's infiltration formula is valid only where rainfall intensity at all times exceeds infiltration and, moreover, it does not provide adequately for the handling of a variety of initial soil moisture conditions. In contrast to Horton's concept where infiltration rate is expressed as a decay function of time, the procedure advocated in this paper expresses the infiltration rate as a function of soil moisture storage state. The procedure permits infiltration losses during intermittent rainfall sequences to be evaluated and accommodates a range of initial soil moisture conditions.