PERFORMANCE OF THE STEADY-STATE DIPOLE FLOW TEST IN LAYERED AQUIFERS

Steady-state numerical simulations of the dipole flow test in layered aquifers demonstrate that the test produces a good estimate of the equ ivalent hydraulic conductivity anisotropy ratio for the part of the aq uifer spanned by the well chambers. The effects of chamber size, diffe rent conductivity of layers and layer location on the estimated anisot ropy ratios are presented. The steady-state dipole flow test, when per formed at different levels in the well, can yield estimates of the dow n-hole anisotropy ratio distribution. Numerical simulations also illus trate that the skin effect can significantly distort the anisotropy es timates produced by the dipole flow test. (C) 1997 John Wiley & Sons, Ltd.