The subject is a hydrological analysis of a karst system using the instruments of the data assimilation field of study, in particular the Ensemble Kalman Filter. In particular, the analysed system is the karst complex of Bossea-Artesinera, located in the south of Piedmont. The aim is to characterize the response of the aquifer in response to a meteoric precipitation. To do this we used a response initially composed by an infiltration coefficient and an instantaneous unitary hydrogram (IUH). So, the response of the system can be modelled using a number of state parameters, and an output can be calculated from them as an outcoming rate flow.