Darcy’s Law

Definition

Darcy’s law defines the rate of water flow through porous media, assuming a laminar flow. It states that the rate of flow per unit, cross-sectional area is equal to the product of the hydraulic conductivity of the material and the hydraulic gradient.

Overview

Henry Darcy (1803–1858), a French waterworks in Dijon, revealed a proportionality between the flow rate in clean sand and the applied hydraulic gradient. In its simplest form:

$$ q= vA= kiA=k\frac{\Delta h}{L}A $$

(1)

where q is the flow rate through the cross-sectional area (A); v is the flow velocity; i is the hydraulic gradient, calculated as the difference in pore pressure head per unit length (Δh/L); and k is the hydraulic conductivity.

Use

Darcy’s law is widely used in the fields of Engineering Geology, Hydrogeology, Geotechnical Engineering, and Environmental Sciences, in particular for estimating seepage rates, flow patterns, drainage, and contaminant transport through Earth materials. Darcy’s law can be...