The problem of simulating the topsoil dynamics in response to atmospheric evaporative events is considered in the present paper. It is emphasised how the assumption that soil moisture profiles approximately preserve similarity during simultaneous atmospheric drying and gravity drainage may be required in order to incorporate the effects ofdeeper soils in the near-surface soil control volume hydrologic modelling. The reliability of the proposed formulation is evaluated with rates of evaporation calculated from measurements of the Bowen ratio and soil moisture data obtained from time domain reflectometry measurements for a bare soil field in the Zwalmbeek catchment (Belgium).