Volume 12, Issue 4 (December 1989)
A Note on Falling Headwater and Rising Tailwater Permeability Tests
Falling-head permeability tests may be performed in two ways: (1) with a constant tailwater pressure and (2) with a rising tailwater pressure. Equations published in textbooks and manuals for calculating hydraulic conductivity from a falling-head test are for the first type of test only and are in error by a factor of 2 when applied to the second type of test. The correct equations for calculating hydraulic conductivity for both types of test are derived and confirmed.