The small town of Yport in the northern part of the Pays de Caux, Normandy, is located on the shore of the English Channel between Étretat and Fécamp, at the outlet of a long dry valley that incises the chalk plateau. Eight hundred metres to the east, at the base of a cliff, is a cluster of springs, the ‘Fontaines d'Yport’, that emerge on the foreshore. Given their high discharge, measured at between 1 and 2.5 m³ s⁻¹, the Le Havre authorities have been interested in these springs since the 1960s, in determining their origin, locating the karst conduit, developing them, and investigating the boundaries and vulnerability of the groundwater basin. Today, one third of the drinking water that supplies the Le Havre conurbation comes from the Yport wells, and investigations into their vulnerability and protection of their resource continues.