The Rhone Sediment Observatory


The mission of the observatory is to compile and manage data on sediment dynamics and associated contaminants. Overall, these data should help river managers and stakeholders. The observatory is a multi-partner platform aiming to carry out collaborative research between scientific researchers and managers.

The obsevratory is funded through the “Plan Rhone” and benefits from support from the European Regional Development Fund (ERDF). The observatory includes scientific institutions (CNRS, INRAE, ENTPE, IRSN, IFREMER) and the main river managers (DREAL, Agence de l’Eau, CNR, EDF, the Rhone-Alpes, Provence-Alpes-Cotes d’Azur, and Languedoc-Roussillon Regions). It is one of the Zone Atelier du Bassin du Rhone (ZABR) observatories.

The main objective is to study the whole Rhone River valley, more than 500 kms from Lake Geneva to the Mediterranean Sea. The entire river corridor is considered, and it encompasses the active channel, reservoirs upstream of hydroelectric dams, and alluvial margins. There goal is to understand the different components of the hydrosystem (upstream – downstream continuum, differences between left and right banks, connection between the river and the coast). The sediment mass balance and the hydro-sedimentary dynamics are studied across timescales ranging from a century to instantaneous.

OSR research is structured around five thematics. Specific actions are aimed to resolve scientific questions that will provide concrete response to questions facing river managers in the areas of risk management and sustainable development of the fluvial and marine ecosystems.

Scientific objectives

The OSR goal is to improve scientific understanding of the Rhone River (sediments flux and fluvial landforms), and to inform river managers in order to help decision making and environmental policies implementation. At the scale of large rivers like the Rhone River, the issues are complex. Therefore, we propose to combine scientific approach and technical and operational aspects.

The main research objectives are :

  • To understand the channel evolution in order to improve the link between sediment dynamics and flood risk, and to promote integrated management.
  • To manage the sediment deficit and its impacts, notably on the delta and the Mediterranean coast.
  • To understand the transfer of sediments and associated contaminants to the Mediterranean sea, and to identify the role of different tributaries to the whole corridor.
  • To identify the link between sedimentary forms, and aquatic and fluvial habitats in order to protect and restore them.
  • To analyze the impact of various practices (dredging, flushing, deforestation) on sediment storage in fluvial features.
  • To produce, centralize, structure, and archive data on Rhone River sediments in order to improve knowledge and diffusion to managers, decision makers, and citizens.

Overall, the OSR aims to understand the spatial and temporal variability of the Rhone River sediment dynamics using a comparative and multi-scale approach (longitudinal variability, comparison of bypassed river segments and reservoirs, contribution of single events, seasonal fluctuation, inter-annual and long-term evolution), and to characterize the evolutionary trajectory of the system.

Several research topics have been defined with the following objectives :

  • To quantify the transfer of suspended and bedload sediments at different time-scales (centennial, inter-annual, event-based).
  • To quantify the flux of organic and mineral contaminants associated with the sediments.
  • To study the relationship between fluvial dynamics and morphodynamic processes in the delta and littoral zone, and to calibrate morphodynamic models for predicting coastal evolution.
  • To establish a sediment budget that integrates longitudinal discontinuities and the role of management.
  • To characterize sediment storage (reservoirs and alluvial margins), and to establish a classification of sedimentation history.
  • To understand the repartition of stored hydrophobic pollutants and remobilization processes.
  • To model flow and to evaluate the hydrologic and hydraulic consequences of recent sediment history on the river corridor.
  • To analyze the effects of climate changes on the fluvial-sedimentary dynamics and on the fluvial-coastal interface.

In order to address these challenging issues, we established a collective, interdisciplinary, and long-term approach.

Lab and Field work