The Val d’Orléans is a vast depression in the Loire River main flow, 37 km long and from 4 to 7 km wide. This is a saturated karst aquifer, hosted within a carbonate lacustrine deposit called the Beauce limestone with a high porosity overlain by the Quaternary alluvia of the Loire River. The Loire River feeds more than 80% of the water hosted in the carbonate karst aquifer (11.5 m3/s during low water periods). Water outflows toward several resurgences of the Loiret River through a saturated karst networks.