Technical Abstract: Rill and gully development are usually thought of as a consequence of overland flow in which at selected locations in the landscape the shear stress has exceeded a threshold value. In those cases, the flow regime causes local scour that might lead to headcuts and incisions in the concentrated flow pathways. In most of these studies, the role of the subsurface water regime as a contributing factor is being ignored. Field and laboratory studies have shown that in addition to surface flow, the subsurface soil water regime may appreciably affect conditions for incipient rilling and ephemeral gully development. Also, in places where the groundwater table intersects the surface topography, seepage occurs that leads to localized soil erosion which manifests itself in terms of incisions and headcuts. This article summarizes an analysis of the subsurface flow regime in a homogeneous isotropic aquifer with a water table that is higher than the water level in the incised drainage ditch. The aquifer with a finite depth has an open surface boundary and is infinite wide. To facilitate the analysis, a steady state flow condition is considered in which the analysis is based on a solution of Laplace’s equation for the flow region. Expressions for the exit gradients at the water/soil inter-phase were determined. The model considers a buffer strip where no water enters the soil profile. Estimates are made for seepage losses for different buffer strip widths. The analysis yields a close-form solution for this simplified physical realization that will facilitate estimations of subsurface flow in runoff and erosion models.