Lower boundary condition

If there is a horizontal drainage of water from the profile (i.e. if the lower boundary is saturated) some of the dissolved salt will be lost by leaching. The amount of leached salt, q_Cldr, is proportionate to the total amount of drainage water, q_dr:

                                                         (2.58)

where C_Cllow is the salt concentration in the bottom layer of the soil profile.

Analogously to this flow, there is a salt flux connected to the deep percolation of water, q_Cldp:

                                                       (2.59)

where q_deep is the deep percolation of water.