FIELD MEASUREMENT OF SATURATED HYDRAULIC CONDUCTIVITY DRAINABLE POROSITY USING GUYON’S PUMPING TEST

ABSTRACT Guyon's pumping test is used to measure in situ values of two soil hydraulic parameters used for drainage design purposes, the horizontal component of saturated hydraulic conductivity, and the drainable porosity. If the well reaches the barrier, the test gives the equivalent horizontal hydraulic conductivity of layers above the barrier. If not, it provides the average hydraulic conductivity of layers extending from water-table to the barrier. The method has two advantages: 1) both theoretical basis used to compute soil properties and drain spacing are identical, and 2) the radius of influence is a few meters, so that both soil hydraulic properties are field effective values. As a result, the method is more precise than the auger-hole method: five to ten auger holes are required to measure the hydraulic conductivity with the same precision as Gyon's method.