Analysis of a long-term pumping and tracer test using the channel network model

Abstract

Water flow and solute transport in a fractured medium are described by the Channel Network model, CHAN3D. In the field and in the model, most of the flow and transport take place in fracture zones. CHAN3D was used to simulate a long-term pumping and tracer test called LPT2. In the first simulations, no calibrations, conditioning or parameter adjustments were made to better fit the experimental results. Instead, as much as possible of the available field data were used. In six different paths the simulations predicted breakthrough that should be observable. However, only two of the performed tracer tests resulted in breakthrough of solutes. Some possible reasons for the scant recovery is discussed. In the analysis of LPT2, the impact of the flow rates at the injection positions, flow porosity and interaction with the rock matrix were studied.