Long-term high-frequency salinity, temperature and water level across an intermittent Mediterranean river-estuary continuum : the Fiume Santu (Corsica)

Estuaries, acting as interfaces between the land and the sea, provide vital ecosystem services, considered as biodiversity hotspots. Under a Mediterranean climate, they undergo strong hydroclimatic variability, receiving no freshwater to flash floods and being intermittently connected to the sea. We present a ready-to-use dataset, including quality-controlled surface and groundwater measurements along a small Mediterranean temporarily closed estuary: the Fiume Santu estuary (Corsica). Salinity, temperature and water level were measured hourly for a maximum of seven years, from 2014 to 2022, using multi-parameter probes. Multi-annual recordings highlight the intermittency of connection between aquatic compartments and the buffering role of the estuary, recording recurring extreme events such as floods, estuarine mouth closures or hypersalinity. The long-term high-frequency hydrological recording of the associated surface and groundwater measurements of a temporarily closed estuary, being unique, offers a new medium for a large panel of scientists and environmental managers to expand in terms of environmental groundwaterconditions considered in coastal and estuarine studies.