HR: 0830h
AN: H31D-0492    [PDF]
TI: Studies on Water Phase and its Movement in Unsaturated Porous Media
AU: * Aoda, T
EM: aoda@agr.niigata-u.ac.jp
AF: Faculty of Agriculture, Niigata University, 8050 Ikarashi-2, Niigata, 950-2181 Japan
AB: Soil water moves not only in liquid phase but also in vapor phase even in constant temperature laboratory. The test column that consists of glass beads with diameter of 0.1mm controlled water pressure by lowering water level. We measured water pressure of the test column by using micro-tensiometer at three cross sections and in three directions during four months. The experimental results indicated as follows; 1) In the funicular stage, at every measured point water pressure obeyed hydrostatic pressure until threshold value -90cm. Hence the maximum possible height of this column was 90cm in drying process. 2) Since the value of tensiometer represent pressure of liquid phase water in porous media became independent and forms pendular ring. 3) Lowering water level further, the column became film stage in which contains pendular ring and adsorbed film. In some points water pressure observed constant value about -90cm. Others changed in wide range from -90cm to -630cm. 4) Though macroscopic trend of change of water pressure was not related to each other, microscopic trends synchronized. 5) Consequently driving force of water movement in vapor phase was not pressure but potential especially in film stage.
DE: 1829 Groundwater hydrology
DE: 1866 Soil moisture
DE: 1875 Unsaturated zone
SC: Hydrology [H]
MN: 2003 Fall Meeting