Subsurface storm flow can be explained by quick response of groundwater flow to infiltration. The corresponding fast infiltration from the soil surface to the saturated soil layer is here approached by macropore flow concepts that are based on kinematic flow theory. The distribution of the flow parameters (i.e., macropore conductance, b, and sorbance, r), that are used to represent the macropore flow processes within a given soil, are derived upon the separation of drainage hydrographs. The approach is valid over time intervals lasting about twice the duration of water input to the surface. The drainage hydrographs were obtained by sprinkling on an undistrubed block of forest soil. The block was underlain by impermeable glacial till. The macropore flow distribution function model creditably reproduced the hydrograph time to peak for a number of experiments. The importance of saturated layers on the generation of subsurface storm flow is demonstrated.