Water Flow in Soil

The final transport equation that we need to consider is Darcy’s law (Eq. (6.4)). This law describes the transport of water in porous materials such as soils. Darcy’s law describes most of the water flow that takes place in soils. Since water plays such an important role in the energy balance of soils, plants, and animals, an understanding of at least some simple applications of Darcy’s law is important to environmental biophysicists. The processes that are important in determining the water budget of a soil are infiltration of applied water, redistribution of water in the soil profile, evaporation of water from the soil surface, and transpiration of water by plants.