Radicatel springs are a major historical site for drinking water production for the city of Le Havre and its suburbs (255 000 inhab.). This karst system is on the right bank of the Seine and its downstream hydraulic (the Seine) underwent a staging and diffluence in response to fluctuations in base level during Pleistocene. The geomorphological structure coupled to a structural context dominated by the fault-Lillebonne Fecamp, determines the hydrological behavior and vulnerability of the karst system. The study of this system is realized in three stages: (i) analysis of the influence of climate variability, (ii) study of the structural setting at the regional and local levels and (iii) the study of hydrological behavior of three sources (Moulin B, Bruisseresse and Four aux veaux) with a high frequency monitoring of turbidity and electrical conductivity (15 min). The multi-disciplinary analysis showed the link between changes in hydro-sedimentary signals (turbidity and sedimentary record) and changes in the climatic index NAO. These results demonstrate that the karst Radicatel has very strong connections thanks to sinkholes with water from runoff. In this climate control plus a marked structural control by the presence of a fault oriented N150 between the source of the Moulin B and the source of Bruisseresse, secondary fault N50-60, and a unique morphology of top of the Albien. This structural and hydrogeological context is part of a graben compartments seat of a very large karst aquifer. The study of the hydrological behavior of the three sources by signal analysis of turbidity and electrical conductivity confirms the existence of a common character-specific chalk aquifer, and functions for each source connected to the local influence of morpho-tectonic context locally.
