Question

If Brooks and Corey equations are used to describe the unsaturated flow in a silt loam ( n = 0.396, Theta(r) =0.131, Hb = -236.4 cm, lambda =1.0 and K s = 4.96 cm/day). Calculate soil water diffusivity at soil moisture content = 0.3.

Answer 1

given

n = 0.036

_r = 0.131

H_b = -236.4

= 1.0

K_s = 4.96 cm / day = 5.74 X 10^-7 m/sec

soil moisture content = 0.3

D =  

the force size distribution

n' = 1+n

= 1 + 0.396 = 1.396

m= 1-(1/n')

= 1- (1/1.396) = 0.284

Se = effective solution

Se =

where

= 1 X 10^-4

Se = 1 X 10^-4

h = H_b = =236.4 cm

= 236.4 cm = 2.364 m

Se =

Se = 0.9999

soil water diversity is

D =

D = 0.08583 m²/sec Ans