PNNL

Abstract

Pressure plates are used routinely to measure water retention characteristics of soils. Plates of varying porosity are used depending on the pressure range of interest. For applied pressures up to 1.5 MPa, 15-bar porous ceramic plates with fine porosity are used because of their high bubbling pressure (>15 bar), which limits airflow through the plate. The typical saturated hydraulic conductivity of the 15-bar plate is less than 1x10-13 m s-1. Low plate conductance coupled with decreasing soil hydraulic conductivities (e.g.,