摘要：The large spread in length scales present in the hydrological problems (i.e. province of Santa Fe basin systems) requires a high degree of re nement in the nite element mesh and, then, requires very large computational resources. Also, in a 2D multiaquifer model, the number of unknowns per surface node is, at least, equal to the number of aquifers and aquitards. Moreover, if a pollutant transport model is used with the velocity eld results, then it is desirable to have several sub-layers inside the aquifer in order to recover the vertical gradient, which drives the transport of pollutant between aquifers. This increases the number of unknowns and, also, the band-width of the associated FEM matrix, so that the total computation time is roughly proportional to the square of the number of vertical layers and sub-layers. Due to this fact, it is expected to have a very high demand of CPU computation time, calling for parallel processing techniques. A large scale C++ parallel FEM module using a general advection-di usion PETSc-FEM code was written for hydrological problems. Several systems of aquifers/aquitards coupled with a net of surface streams can be solved. The streams can be modelled with the KWM (Kinematic Wave Model) approximation, 2D or 1D Saint-Venant model. There is mass exchange between streams and aquifers through a resistance coecient at the stream walls. Both Manning and Chezy friction models are available for the streams. Absorbent boundary conditions are implemented in order to avoid wave re ection for Saint-Venant models.
