Figure taken from Hornberger et al. (1998)

Linear flow paths assumed in Darcy’s law True flow paths

Figure taken from Hornberger et al. (1998) Darcy’s original data for two different sands.

Figure taken from Hornberger et al. (1998)

Vector Form of Darcy’s Law Q = - K A (  h/  l) q = - K grad h q = specific discharge (L/T) K = hydraulic conductivity (L/T) grad h = hydraulic gradient (L/L) h = head (L)

Scalar 1 component MagnitudeHead, concentration, temperature Vector 3 components Magnitude and direction Specific discharge, (& velocity), mass flux, heat flux Tensor 9 components Magnitude, direction and magnitude changing with direction Hydraulic conductivity, Dispersion coefficient, thermal conductivity

Inflow = Outflow Recharge Discharge Steady State Water Balance Eqn.

Hornberger et al., Elements of Physical Hydrology, The Johns Hopkins Press, Baltimore, 302 p.