HR: 16:35h
AN: H22J-03    [PDF]
TI: Experimental Measurements of Saturation Overshoot on Infiltration
AU: * DiCarlo, D A
EM: ddicarlo@ars.usda.gov
AF: USDA-ARS National Sedimentation Laboratory, 598 McElroy Dr, Oxford, MS 38655
AB: Gravity driven fingers in uniform porous media are known to exhibit saturation overshoot with saturated (or nearly so) tips and much less saturation in the tails. We find that constant flux infiltration into confined (smaller than the finger width) porous media produces saturation overshoot identical to that found in gravity driven fingers. Using light transmission, the saturation profiles were measured as a function of infiltrating flux, porous media grain size, grain sphericity and initial water saturation. Saturation overshoot ceases below a mininum in infiltrating flux which depends greatly on grain sphericity and initial water content and slightly on grain size. We will discuss how the measured 1-D saturation overshoot is inconsistent with continuum models of porous media, but qualitatively matches well predictions using pore filling mechanisms. This suggests that pore-scale physics controls saturation overshoot and in turn gravity driven fingering.
DE: 1832 Groundwater transport
DE: 1866 Soil moisture
DE: 1875 Unsaturated zone
SC: Hydrology [H]
MN: 2003 Fall Meeting