4 Darcy’s Law, Head, Gradient and Hydraulic Conductivity

Knowledge of the porosity, void ratio, moisture content, specific yield and specific retention of earth materials are needed to understand how soil water and groundwater are stored in earth materials and were discussed in Section 3. Properties that characterize the transmission of water through earth materials are presented in this section. To develop these concepts, Darcy’s Law, which governs groundwater flow in porous media, is presented; and head, gradient and hydraulic conductivity components are defined and explained.