BY-CHAMBER INTERPRETATION FOR RESOLUTION ENHANCEMENT OF STEADY-STATE DIPOLE-FLOW TESTS

Over the last decade the dipole-flow test (DFT) evolved from the general idea of using recirculatory flow to evaluate aquifer properties, to the development of prototype instrumentation and feasibility studies, to a reliable tool for characterization of aquifer heterogeneity. The DFT involves the interpretation of head in recirculatory flow between injection and extraction sections (chambers) in a single well isolated from each other by a multi-packer system. In previous studies, estimates of horizontal hydraulic conductivity Kr were based on the steady-state head difference between chambers. A new "by-chamber" interpretation is proposed that is based on drawdown within each individual chamber. It is shown that head-difference based interpretation yields a harmonic mean of data from by-chamber interpretation that introduces the additional averaging into Kr estimates. The results from two sites (Horkheimer Insel site, near Heilbronn, Germany, and Management System Evaluation site, near Shelton, Nebraska, USA) indicate that this interpretation yields more detailed information on structure of the aquifer heterogeneity without introducing complexity into the analysis.