The Agly watershed is regularly subjected to heavy floods due to intense precipitation. However, in equivalent rain, streams do not react in the same way depending on the level of water present in the karst. Understanding the functioning of karst is therefore essential in order to anticipate the floods of the Agly and thus best adjust the methods of warning and crisis management. This research program involves analysing hydrological, rain and piezometric data sets in order to model the functioning of the karstic sector and thus of the Agly and its tributaries. The model will lead to operational tools that will make it practical to better anticipate the magnitude of floods and to adapt the response in terms of vigilance, alerting and crisis management