Abstract
The well-known Horton equation is still one of the most frequently used models defining the infiltration of water into soil. The Horton equation has been criticized because it has no theoretical basis, and because direct analytical methods are not available for the determination of the three parameters defining the equation. This paper presents a nonlinear least-squares scheme for estimating the initial infiltration rate, fo, the final infiltration rate fc, and the rate constant, K, which define the Horton equation. For the four case studies investigated, the performance of the Horton model in estimating the infiltration volume was observed to be excellent.