Infiltration from Constant‐Head Well Permeameters and Infiltrometers

Infiltration from constant-head well permeameters and ring or disk infiltrometers takes place under conditions of three-dimensional transient and steady state flow. Under positive head conditions (i.e., ponded infiltration), both the saturated and unsaturated components of hydraulic conductivity (i.e., field-saturated hydraulic conductivity and matric flux potential, respectively) determine the early-time transient and steady-state flow rates. Under negative head conditions (i.e., tension infiltration), the early-time transient and steady-state flow rates are determined only by the appropriate range of the unsaturated hydraulic conductivity (i.e., the tension flux potential). Several approaches are presented and discussed for determining the saturated and unsaturated components of hydraulic conductivity from well permeameter and infiltrometer measurements.