4. Evolution of modeling systems

At present, 1D, 2D and 3D modeling systems (MASCARET-TELEMAC system, developed by EDF R&D, Mike-DHI system, Delft 2D and 3D, etc.) (cf. [Doc. P 4 237]) in river and marine hydraulics provide satisfactory answers to most of the studies required for development projects. Nevertheless, the evolution of simulation in the hydro-environmental field, combined with the ever-increasing power of computers (appearance of the GPU Graphics Processing Unit technique, parallelization of calculation codes, use of calculation clusters) and the acquisition of field data made less and less costly by new generations of sensors, has led to the emergence of new needs that would not have been envisaged until recently:

• process modelling over vast areas and long periods of time (watersheds of several tens or hundreds of thousands of square kilometers, simulation...