Modeling the effects of surface storage, macropore flow and water repellency on infiltration after wildfire

Abstract

Wildfires can reduce infiltration capacity of hillslopes by causing (i) extreme soil drying, (ii) increased water repellency and (iii) reduced soil structure. High severity wildfire often results in a non-repellent layer of loose ash and burned soil overlying a water repellent soil matrix. In these conditions the hydraulic parameters vary across discrete layers in the soil profile, making the infiltration process difficult to measure and model. The difficulty is often exacerbated by the discrepancy between actual infiltration processes and the assumptions that underlie commonly used infiltration models, most of which stem from controlled laboratory experiments or agricultural environments, w..