Fig. 7. Example influence of layering. Close-up photographs of the (a) bottom and (b) side of the plume at about 30 h. At the bottom, water appears to be preferentially flowing parallel to small-scale cross bedding after breaking through a stronger horizontal capillary barrier at the top of unit 3 (white arrow). At the side, these sequential capillary barriers allow effective horizontal flow. Note, these photographs should be seen in color and are best viewed on a computer screen where one can "zoom in" to see increasing detail.