Simulation of solute transport in discrete fracture networks using the time domain random walk method

The time domain random walk (TDRW) method has been developed for simulating solute transport in discrete fracture networks. The following transport processes have been considered: advective transport in fractures, hydrodynamic dispersion along the fracture axis, sorption reactions on the fracture walls and decay reactions. The TDRW method takes advantage of both random walk and particle-tracking methods. It allows for the one-step calculation of the particle residence time in each bond of the network while avoiding mass balance problems at fracture intersections with contrasted dispersion coefficients. The accuracy of the TDRW method has been addressed by means of synthetic test problems into single fractures and into a 2D discrete fracture network. In each case, simulated and theoretical results compare very well.