Guelph constant head permeameter The Guelph permeameter is a ‘constant head’ permeameter that operates in accordance with the principle of the Mariotte bottle. After boring a hole the Guelph permeameter is placed. The water from the permeameter slowly flows into the auger hole and penetrates into the soil. At a certain moment a saturated ‘bulb’ is formed and the out-flow of water from the storage cylinder reaches a constant value (that is measured). These measuring data together with the diameter of the auger hole and the level of the water in the auger hole, are used to determine the (saturated) hydraulic conductivity of the soil. Benefits Guelph constant head permeameter · Determines permeability in root zone · Meant for above the groundwater table · Steady state principle for optimum accuracy Simple operation Remarks · Must be supported in windy weather Availability The complete standard set, for measurement up to a depth of 75 cm, fits in a carrying bag and, among other items, contains: the Guelph permeameter, a tripod, drill bits, a vacuumtest manual pump, a fold-up jerry can and various accessories.