New statistical grain-size method for evaluating the hydraulic conductivity of sandy aquifers

A new statistical grain-size method of evaluating the hydraulic conductivity and transmissivity of sandy aquifers is presented. The new equation is of the form K = Cd210 and is similar to the existing equations, but in this case the coefficient C, which is normally taken as a constant is actually shown to be a variable that depends on the nature of the geologic environment (source rock, transportation, deposition and post-deposition history, etc.). It is established that C for unconsolidated and poorly cemented sandy materials is 6.0, for moderately consolidated/cemented rocks, C = 3.8, while for fairly well compacted and cemented rocks, its value is about 2.0. With these coefficients, the new statistical grain-size method gives K and T values that compare favourably with those determined from pumping test methods. © 1989.