Dataset of physico-chemical variables for a full-year time series characterization of Hyporheic zone of Selune River, Manche, Normandie, France

Résumé 0

This dataset presents field measurements that documents the physical and chemical response of riverbeds in the context of critical hydrological and sedimentary forcing in the Selune River (France). The river flows into the bay of Mont Saint-Michel and thus impacts numerous economical activities and spawning of several key species such as Atlantic salmon and lamprey. To restore the hydro-sedimentary continuity of the river, two dams are currently being removed. Important changes in the stream flow regime, the stream-aquifer exchanges and the sediment transport are expected, motivating the monitoring campaign. A network of high frequency autonomous sensors (water level, temperature, conductivity, oxygen and pressure differential) was installed in the river and the riverbed at various depths, to continuously record the variation of the main physico-chemical variables and relate them surface processes. To assess the impact of dam removal on these variables, two measurement sites were chosen, upstream of the dams where flow conditions remained stable and downstream of the dams where a large amount of fine sediment has been released. This original data can be used to uncover the biogeochemical functioning of the hyporheic zone and its coupling to dynamical flow and sedimentary processes.