Capillary-tube infiltration model with Brooks-Corey parameters

Recent studies on soil water movement emphasize the description of soil macropore flow. In this article, an infiltration model is developed which separates water flow in large soil pores from flow in small pores. The soil water retention curve is considered to represent a bundle of capillary tubes. The matric potential of the retention curve is used to determine capillary tube hydraulic conductivity based on Hagen-Poiseuille equation. Infiltration capacity curves under a surface ponded condition are derived. The model predicts a spatially varied wetting front. An example to illustrate the application of capillary-tube infiltration model to determine the spatially wetting front of Yolo light clay is presented.