This paper presents preliminary results from two karst systemsbelonging to the ‘‘Jurassic Karst’’ observatory in the French Jura Mountains. Thesites are characterized by localized and diffuse recharge. Physicochemical monitoringwas performed at the karst outlet (springs), as well as in the unsaturatedzone (cave and epikarstic spring). During two contrasting flood events, water level,temperature, electrical conductivity, dissolved organic carbon, turbidity, and dissolvedoxygen were recorded at high frequency and compared. These preliminaryresults allow to propose a conceptual model for both sites. It was possible todistinguish specific autogenic and allogenic recharge mechanisms and to characterize the respective contribution of the saturated and unsaturated zones.