INFILTRATION UNDER PONDED CONDITIONS .3. A PREDICTIVE EQUATION BASED ON PHYSICAL PARAMETERS

We derived a new infiltration equation that takes into account the possibility of an infinite diffusivity near saturation. Using the example of two soils (clay and coarse sand), we showed that this new infiltration equation has a sound physical basis. In particular, all parameters used are true soil properties that are constant with time and independent of the water depth imposed as a surface boundary condition. Compared with analytical, numerical, and experimental results, the equation shows a great precision (σ2< 5.10−3cm2) at all times. The present law introduces a significant improvement over the law obtained in part 1 of this series dealing with ponded infiltration by introducing the physical effect of an infinite diffusivity at saturation. © 1990 Williams & Wilkins.