van Genuchten Model

For h < 0:

s_e = 1 / (1 + |alpha*h|^beta)^gamma

Kr = ( 1 - C * D ^(-gamma) )² / D ^(gamma/2)

C = |alpha*h| ^(beta-1)

D = 1 + |alpha*h| ^beta

For h >= 0:

s_e = 1

Kr = 1

where

s_e = effective saturation = (VMC - RMC)/(porosity - RMC)

• VMC = volumetric moisture content
• RMC = residual moisture content

Kr = relative hydraulic conductivity

h = pressure head

alpha = parameter, see Note to VS2DH 1.0 users

beta = parameter

gamma = 1 - 1/beta

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