comparison of soil saturated hydraulic conductivity under shallow well and guelph permeameter method above the water table

to design subsurface drainage systems, it is necessary to determine the saturated hydraulic conductivity of the soil. one of the most common methods for field measurement of this parameter is the shallow well pump-in test method. another method which has recently been introduced for the above measurement is the guelph permeameter method. both methods are used to measure the soil saturated hydraulic conductivity in the field above the water table, where the main purpose of drainage is to prevent rising the water table or to leach the excess salts from the root zone. to compare shallow well method with the guelph permeameter method, field measurements were conducted under the same conditions at two different fields. from comparisons of the two methods it was resulted that the shallow well pump-in test method is able to measure a more complete trend of soil infiltration variability (and finally the saturated hydraulic conductivity) with respect to time, although the guelph permeameter method is able to measure this parameter of the soil in a much shorter period of time. a computer model, named gefi (general equation for infiltration), was used to fit the field data. the results showed that the model is able to closely fit field data for both methods and predict the soil saturated hydraulic conductivity.