Rainfall interception by plant canopy is one of the processes that induce heterogeneity in water status at the plot scale. Many studies have quantified the impacts of rainfall partitioning and redistribution by vegetation on spatial patterning and dynamic of soil moisture content, evapotranspiration, percolation and surface runoff. Nonetheless, few models represent the effects of rainfall redistribution by canopies on soil water and solute fluxes. Moreover, this phenomenon is most often neglected when modelling catchment runoff. In this paper we present an original modelling approach developed for simulating the impact of rainfall distribution by canopies on water and solute fluxes at the field and catchment scales. The modelling approach couples a stemflow model with a soil water balance model and distinguishes two within-plot compartments with separate water balance calculations: one compartment receiving stemflow and another compartment for the rest of the plot. The approach was evaluated in an actual case study on volcanic soils in the French West Indies where banana canopies redistribute intensely rainfall and thereby influence largely the patterns of water and pesticide flow (Cattan et al., 2007; Saison et al., 2008; Charlier et al., 2009). At the field scale, the application of the model was compared to that of a similar water balance model without stemflow processes to predict surface runoff. The results obtained clearly showed an improvement in performance of runoff predictions when rainfall interception by bananas is considered. A the catchment scale, the model with stemflow was included in a coupled surface-subsurface flow model to predict catchment runoff. Sequential calibration of the components of the catchment model enabled to reproduce satisfactorily the main dynamics of catchment runoff. The stemflow model allowed to simulate a significant contribution of Hortonian runoff to catchment runoff. Work is ongoing to link the simulation of hydrological processes to pesticide transfer from plot to catchment. Cattan, P. Voltz, M., Cabidoche; Y.-M., Lacas, J.-G., Sansoulet, J. 2007. Spatial and temporal variations in percolation fluxes in a tropical Andosol influenced by banana cropping patterns. Journal of Hydrology, 335, 157– 169. Saison, C., Cattan, P., Louchart, X., Voltz, M. 2008. Cadusafos fate on banana cultivated Andosols in humid tropical conditions as influenced by heterogeneous application pattern and within-canopy rainfall. Journal of Agricultural and Food Chemistry, 56(24), 11947-11955. Charlier, J. B., Cattan, P., Moussa, R., Voltz, M. 2009. Transport of a nematicide in surface and ground waters in a tropical volcanic catchment. Journal of Environmental Quality, 38, 1031-1041.