ABSTRACT
Water entry into the soil by infiltration is among the most important of soil hydrological processes, as it controls the partitioning between runoff and soil water storage. Runoff water determines the surface water’s quantity and quality, whereas infiltrated water determines the plant’s available water, evapotranspiration, groundwater recharge, and groundwater quality. Also through exinfiltration, infiltrated water can affect the surface water’s characteristics as in riparian zones. Yet, despite its relevance and our solid physical understanding of infiltration, we have generally great difficulty in predicting the infiltration in the field at larger spatial scales. Mostly, this is so because the infiltration rate is a time-varying quantity that is highly dependent on soil properties that are generally highly variable in space, both in the vertical and horizontal directions of the hydrologic basin. Moreover, infiltration rate and runoff are affected by vegetation cover, as it protects the soil’s surface from the energy impacts of falling rain drops or intercepting rainfall, serving as a temporary water storage. The kinetic energy of rainfall causes soil degradation, leading to soil surface sealing and decreasing infiltration.
