The model MHYDAS (Moussa and al., 2002, Hydrol. Process. 16), developed by the LISAH since decade, allows the simulation of the hydrological balance assessments, exchanges surfaces-undergroung passages, contaminations and transport of pollutants as well as the erosive transport in ponds anthropisé hillsides. The scales of space go of the plot of land to ponds hillsides of several square kilometers and the scales of time, the rainy event in the multiannual simulations.

MHYDAS consists of procedures of digital representation of the landscape allowing the definition and the paramétrisation of the space (Geo-MHYDAS - Lagacherie and al ., 2010, Computers and Geosciences 36) and of a bookshop of simulators of process of transfers. It is being used through the platform of modelling OpenFLUID.