Preliminary model of saturated flow using Cellular Automata

A fully-coupled from surface to groundwater hydrological model is being developed based on the Extended Cellular Automata formalism (XCA) [1], which proves to be very suitable for high performance computing. In this note, the module related to three-dimensional saturated flow in porous media is presented by using the OpenCAL library [2], allowing to exploit multi-core CPUs and many-core devices like GPUs. The XCA-based model is evaluated in terms of both accuracy and precision of modeling results and computational performance, using two- and three-dimensional test cases at different resolutions (from parcel to catchment scale), simulating pumping from one or more wells, river-groundwater interactions and varying soil hydraulic properties. Model accuracy is compared with analytic solutions, when available, and with the widely used MODFLOW model [3], while the computational performance is evaluated using both CPU and GPU devices. Overall, the XCA-based model proves to be accurate and, mainly, computationally very efficient thanks to the many options and tools available with the OpenCAL library.