Control and reduction of water contamination by pesticides are major issues for the protection of aquatic ecosystems. In order to better understand and formalize the main pathways of pesticides transport, the Catchment Modeling Framework (Kraft et al., 2011) has been chosen, which is an open source hydrological framework providing a spatial distribution with an object-oriented approach. Modularity characteristic of CMF, allows users given a modular design to our landscape, and choose equations describing flux connection between hydrological response units either in surface and subsurface, and to add new modules and functions.