Models in Irrigation andWater Management - Practices of Irrigation and On-farm Water Management - page 398

10.3.3.1 FLOCR

FLOCR is a one-dimensional model that simulates water balance, cracking, and sub-
sidence of clay soils (Bronswijk, 1988; Oostindie and Bronswijk, 1992 ) . The main
feature of “FLOCR” that distinguishes it from other soil-water simulation models is
that this model computes a continuously changing system of soil matrix and shrink-
age crack. The model considers only the vertical water flow through the soil matrix
and through the shrinkage cracks.

Principle of FLOCR

- the soil is divided into soil matrix and cracks.
- The rainfall is divided into matrix infiltration and crack infiltration.
- The crack infiltration is added to the bottom of the cracks, and to the water content
of the soil matrix at that depth.
- The matrix infiltration is added to the top compartment of the soil matrix.

Schematic conceptualization of simulation model “FLOCR” is given in Fig. 10.3 .

Fig. 10.3 Schematic
conceptualization of
simulation model 'FLOCR'
(after Ali, 2000 ) . a
Evapotranspiration; b crack
infiltrationl; c matrix
infiltration; d runoff; e flux to
groundwater; f flux to drain; g
fluxtoaquifer

c

b

d

a

e

g

f

Aquifer

Governing Equations

Boundary Condition at the Top of the Soil Profile

The water balance of the soil surface within one time step is as follows (Oostindie
and Bronswijk, 1992 ) :

S = ( P − E ) − R − V (10.21)

where

V = flux through the soil surface with V = V matrix + V crack (m)