Soil Heat Processes > Soil frost > Theory > Influence of ice on water flows
Infiltration

Infiltration of water into the soil when the soil is frozen can be specified in several ways (see switch Infiltration). The easiest approach is to calculate the infiltration as if the soil was always unfrozen. The other two approaches account for flows in either the low-flow domain or in both the low- and the high-flow domain, based on the same equations for estimation of hydraulic conductivity as described above, Eq (1.34) and (1.35).

At the soil surface, water may infiltrate into the low-flow domain until the capacity of this domain is reached, i.e. the unsaturated conductivity kwf(θlf) times the total water potential gradient. The surplus water enters the air-filled pores in the high-flow domain to a degree that is limited by the conductivity of this domain, khf. Thus an allocation of water from the low- to the high-flow domain takes place (this occurs only if the high-flow domain is considered in the simulation). If the capacity of the high-flow domain is also reached by the snow melt or precipitation, the surplus water will be transferred to the surface pool (see “Surface Water”).