A Capillary Barrier

The video below shows water infiltrating an unsaturated silt (reddish material) in a laboratory apparatus. A coarse gravel zone (gray) is present at the center of the box. As water is applied at the surface, water infiltrates and moves vertically downward due to both gravity and the capillary-pressure gradient. Water running down the insides of the box is drawn laterally into the silt, due solely to capillary-pressure gradients. However, at no time does water invade the coarse zone at the center of the box.







Last modified: Oct 15, 1999
VG Model / Samuel Lee / VADOSE.NET