Incorporating transverse mixing into streamline-based simulation of transport in heterogeneous aquifers

Numerical simulation is an important tool for understanding transport and mixing processes in heterogeneous aquifers. Many studies have shown that streamline-based simulation models are a computationally simple and accurate numerical solution technique. These approaches gain their efficiency by converting the large three-dimensional transport problem into a series of one-dimensional simulations along streamlines. These models are also efficient because they neglect transverse dispersion, thereby allowing all the streamlines to be decoupled. However, for many reactive transport applications, transverse dispersion is a crucial mechanism for mixing various chemicals. We propose a conceptually straightforward method to incorporate transverse mixing into streamline simulation methods based upon using a first-order mass-transfer approximation to transverse dispersion. We describe some details about the new method and present preliminary results for nonreactive and reactive transport.