Abstract To predict plume development in fractured matrix systems without detailed knowledge of the fracture network geometries, a double continuum approach is chosen. The complex transport behaviour can be adequately represented by two overlapping and interacting continua. An existing double continuum approach has been further developed for steady-state flow conditions, with the focus on the mass exchange terms between the fractures and the matrix system. This approach is implemented in the "Double Porosity MT3D" program and has been applied to a transport problem in a fractured porous system. The parameter determination for the fracture continuum is the most important step for calibrating the double continuum model and predicting the plume development adequately. Of particular interest was the determination of hydraulic parameters by fracture network characteristics. The transversal dispersion coefficient and hydraulic conductivity are directly dependent on the angles between the fracture directions and hydraulic gradient. The larger the angle, the higher is the transversal dispersion coefficient and the lower will be the resulting effective hydraulic conductivity.

Keywords double continuum model; fracture networks; transport simulation