This lecture reviews some of the basic concepts about fluid flow through soil including Darcy's Law; Bernoulli's equation; hydraulic conductivity and how we measure it in the lab and field; discharge velocity and seepage velocity; hydraulic gradient; and equivalent hydraulic conductivity in layered soil media (i.e., flow in series and in parallel).

Critical Questions to Consider:
1) What are the two main equations involved in analyzing fluid flow through soil?

2) What is the difference between discharge velocity and seepage velocity?

3) How do we measure total head at a point in the soil? How does using a piezometer help with this?

4) What do you think some of the advantages and disadvantages are of measuring hydraulic conductivity in the lab are? What about in the field?

5) How do we apply Darcy's Law to flow through layered soil media? How is flow in parallel different than flow in series? If I have three layers (1. High permeability, 2. Medium permeability, and 3. Low permeability), which layer would govern flow in parallel? What about in series?