Unsaturated and Saturated Flow Through a Thin Porous Layer on a Hillslope

The subsurface stormflow in a layer of porous earth overlying an impervious hill is investigated in the case when the thickness of the layer is small compared to a typical hill dimension. If the infiltration rate at the surface is low and varies slowly with time, the head is approximately constant along normals to the hillslope, and the flow in both the saturated and unsaturated regions is described by a simple kinematic wave equation. Solutions of this equation describe the spatial and temporal development of the water table as well as the flow in the saturated and unsaturated regions. A numerical example is given.