Unsaturated vertical flows above a water table

An effective conductivity (resistance) for unsaturated vertical flow through horizontal layers of quasi‐linear material above a water table is determined by summing “saturated” resistances in series, subject to an exponential weighting with depth. These effective conductivities essentially determine steady flows, while calculation of intercepts involve weighting changes in water saturation with effective conductivities (resistances) and an exponential function of depth. Exact expressions are determined for the intercept associated with changes in surface values of saturation, and for instantaneous rises in the water table, in a Davidson model soil.