FIELD MEASUREMENT OF HYDRAULIC CONDUCTIVITY WITH A MODIFIED AIR-ENTRY PERMEAMETER

Abstract

The air-entry permeameter procedure for measuring hydraulic conductivity (Bouwer 1966) was modified so that the position of the wetting front was detected during measurement by a fine tensiometer probe. Data obtained by the modified permeameter showed similar magnitude of scatter at each of seven sites on five different soils. Comparisons with data from laboratory determinations on cores (assumed to be representative of the corresponding soil) showed that the permeameter gave reliable values with more consistant precision. The values from the double tube permeameter and the crust method were comparable to air-entry permeameter values. Although further evaluations are desirable, the speed, accuracy, and low water requirement of this permeameter tended to recommend it over other procedures available for measuring the hydraulic conductivity of soils above the water table.