## Calculator 1 - Darcy Flux and Average Linear Groundwater Velocity

Darcy's law is the basic equation that describes fluid flow through porous media. There are many ways to write Darcy's Law, and a few of them will be presented here. The first equation contains a velocity term, v (L/T), a conductivity term, K (L/T), a head term, h (L), and a distance term, l (L):

v = -K(∆h/∆l)

This is the Darcy velocity (or Darcy flux) which is defined as the flow per unit cross sectional area of the porous medium. Since you have a porous media the water must move through the pores, around the solid particles, at a speed greater than the flux. This speed is called the average linear groundwater velocity and is calculated by dividing the Darcy flux by the porosity of the media.