A description of the relationships among factors that determine groundwater flow, expressed as an equation. At its simplest, Darcy's law states that Q = kIA, where Q is the groundwater flow, k the hydraulic conductivity of the rock, I the hydraulic gradient (i.e. gradient of hydraulic head), and A the cross-sectional area through which flow occurs. The law was formulated in 1856 by the French engineer Henry Philibert Gaspard Darcy (1803–58).
Subjects: Earth Sciences and Geography.