are less than atmospheric. Studies of flow in the vadose zone often focus on issues of fingering of water fronts We critically examine historical and recent studies of flow and and characterization of the relationships among moistransport at the local scale within the capillary fringe (CF). The characterization of subsurface pathways traveled by water-and the impact ture content, matric potential, and relative permeability. of these pathways on the movement of chemicals and the viability of In contrast, flow in the groundwater zone is generally subsurface microbial populations-has been the subject of intensive characterized by pores that are essentially saturated investigation in the last 50 yr in the fields of soil science and hydrology.with water. The liquid within the pores is typically at However, consideration of the complexity of local pathways within pressures greater than atmospheric. Flow is no longer the CF has been largely ignored. Recent studies, as well as some predominantly vertical, but reacts to local or regional historical ones, have reported observations of fluid flow and chemical recharge and discharge fluxes, including natural fluxes transport within the CF, emphasizing the impact of physical heterogesuch as recharge from precipitation or discharge to surneity and exchange of water and chemicals between the CF and the face water. region below the water table. These observations lead to the conclu-At the contact between these two zones is a relatively sion that the CF may affect, at the local scale, the natural geochemical and microbial conditions present in the region of transition from narrow region that serves as a transition between the unsaturated to saturated groundwater flow far more significantly than vadose zone and the groundwater zone. Sediments imis usually assumed. Here, we examine underlying physical factors that mediately below the water table, for example, are charcontrol local flow and transport behaviors in and across the CF and acterized by pore water pressures greater than atmoillustrate these factors through examination of images collected in the spheric pressure, and nearly full saturation by the liquid laboratory. We also provide a brief survey of the literature on the phase in most portions of the medium. Also present are CF. It is argued that existing definitions of the CF are inadequate to local zones of entrapped air in the form of bubbles or describe flow and transport behavior in the vicinity of the water table.small inclusions of sediments at low moisture content. We suggest replacing the concept of the CF with the concept of aThe region immediately above the water table contains partially saturated fringe, which involves multiphase transport in the water that essentially saturates the pores, although the immediate vicinity of (both above and below) the water table.