The main of this study is the hydroclimatic modeling chain between a regional climatic modeling and the rainfall-runoff hydrological model GR4J (model of Génie Rural à quatre paramètres au pas de temps Journalier). The hydrological model has been calibrated and validated on small catchments of Burgundy, from desagregated ERA-Interim data at a 3 km scale, and hydrological runoff data at the outlet of the catchments, on the period 1980-2011. The projection of this modeling chain permits to assess the impact of climate change at the small catchments scale, few described.